diff --git a/lib/storage/metadata/oplog/BucketdOplogInterface.js b/lib/storage/metadata/oplog/BucketdOplogInterface.js
new file mode 100644
index 000000000..7550a1f2f
--- /dev/null
+++ b/lib/storage/metadata/oplog/BucketdOplogInterface.js
@@ -0,0 +1,251 @@
+/*
+ * Main interface for bucketd oplog management
+ */
+const async = require('async');
+const { RESTClient: BucketClient } = require('bucketclient');
+const { jsutil, errors } = require('arsenal');
+const LogConsumer = require('arsenal/lib/storage/metadata/bucketclient/LogConsumer');
+const { isMasterKey } = require('arsenal/lib/versioning/Version');
+const OplogInterface = require('./OplogInterface');
+
+class BucketdOplogInterface extends OplogInterface {
+
+    constructor(params) {
+        super(params);
+        this.backendRetryTimes = 3;
+        this.backendRetryInterval = 300;
+        this.bucketdOplogQuerySize = 20;
+        this.stopAt = params?.stopAt ?? -1;
+        const bkBootstrap = params?.bootstrap ?? ['localhost:9000'];
+        this.bkClient = new BucketClient(bkBootstrap);
+    }
+
+    start(filter, cb) {
+        if (!(filter.filterType === 'bucket' ||
+              filter.filterType === 'raftSession')) {
+            return cb(errors.NotImplemented);
+        }
+        const filterName = filter.filterName;
+        async.waterfall([
+            /*
+             * In this step we get the raftId for filterName
+             */
+            next => {
+                if (filter.filterType === 'raftSession') {
+                    return next(null, filter.raftSession.raftId);
+                }
+                this.logger.info('obtaining raftId',
+                                 { filterName });
+                async.retry(
+                    {
+                        times: this.backendRetryTimes,
+                        interval: this.backendRetryInterval,
+                    },
+                    done => {
+                        this.bkClient.getBucketInformation(
+                            filter.bucket.bucketName,
+                            null,
+                            (err, info) => {
+                                if (err) {
+                                    this.logger.info('retrying getBucketInformation', { err, filterName });
+                                    return done(err);
+                                }
+                                return done(null, JSON.parse(info));
+                            });
+                    },
+                    (err, res) => {
+                        if (err) {
+                            this.logger.error('getBucketInformation too many failures', { err, filterName });
+                            return next(err);
+                        }
+                        return next(null, res.raftSessionId);
+                    });
+                return undefined;
+            },
+            /*
+             * In this step we get the stored offset if we have it
+             */
+            (raftId, next) => {
+                let cseq = undefined;
+                this.persist.load(filterName, this.persistData, (err, offset) => {
+                    if (err) {
+                        return next(err);
+                    }
+                    cseq = offset;
+                    return next(null, raftId, cseq);
+                });
+            },
+            /*
+             * In this step we acquire the offset if we don't already have it
+             */
+            (raftId, cseq, next) => {
+                if (cseq !== undefined) {
+                    this.logger.info(`skipping cseq acquisition (cseq=${cseq})`,
+                                     { filterName });
+                    return next(null, raftId, cseq, true);
+                }
+                this.logger.info('cseq acquisition',
+                                 { filterName });
+                async.retry(
+                    {
+                        times: this.backendRetryTimes,
+                        interval: this.backendRetryInterval,
+                    },
+                    done => {
+                        this.bkClient.getRaftLog(
+                            raftId,
+                            1,
+                            1,
+                            true,
+                            null,
+                            (err, stream) => {
+                                if (err) {
+                                    this.logger.info('retrying getRaftLog', { err, filterName });
+                                    return done(err);
+                                }
+                                const chunks = [];
+                                stream.on('data', chunk => {
+                                    chunks.push(chunk);
+                                });
+                                stream.on('end', () => {
+                                    const info = JSON.parse(Buffer.concat(chunks));
+                                    return done(null, info);
+                                });
+                                return undefined;
+                            });
+                    },
+                    (err, res) => {
+                        if (err) {
+                            this.logger.error('getRaftLog too many failures', { err, filterName });
+                            return next(err);
+                        }
+                        return next(null, raftId, res.info.cseq, false);
+                    });
+                return undefined;
+            },
+            /*
+             * In this step we init the state (e.g. scan)
+             */
+            (raftId, cseq, skipInit, next) => {
+                if (skipInit) {
+                    this.logger.info(`skipping state initialization cseq=${cseq}`,
+                                     { filterName });
+                    return next(null, raftId, cseq);
+                }
+                this.logger.info(`initializing state cseq=${cseq}`,
+                                 { filterName });
+                this.persistData.initState(err => {
+                    if (err) {
+                        return next(err);
+                    }
+                    this.persist.save(
+                        filterName, this.persistData, cseq, err => {
+                            if (err) {
+                                return next(err);
+                            }
+                            return next(null, raftId, cseq);
+                        });
+                    return undefined;
+                });
+                return undefined;
+            },
+            /*
+             * In this step we loop over the oplog
+             */
+            (raftId, cseq, next) => {
+                this.logger.info(`reading oplog raftId=${raftId} cseq=${cseq}`,
+                                 { filterName });
+                // only way to get out of the loop in all cases
+                const nextOnce = jsutil.once(next);
+                let doStop = false;
+                // resume reading the oplog from cseq. changes are idempotent
+                const logConsumer = new LogConsumer({
+                    bucketClient: this.bkClient,
+                    raftSession: raftId,
+                });
+                let _cseq = cseq;
+                async.until(
+                    () => doStop,
+                    _next => {
+                        logConsumer.readRecords({
+                            startSeq: _cseq,
+                            limit: this.bucketdOplogQuerySize,
+                        }, (err, record) => {
+                            if (err) {
+                                this.logger.error('readRecords error', { err, filterName });
+                                return setTimeout(() => _next(), 5000);
+                            }
+                            if (!record.log) {
+                                // nothing to read
+                                return setTimeout(() => _next(), 5000);
+                            }
+                            const seqs = [];
+                            record.log.on('data', chunk => {
+                                seqs.push(chunk);
+                            });
+                            record.log.on('end', () => {
+                                const addQueue = [];
+                                const delQueue = [];
+                                for (let i = 0; i < seqs.length; i++) {
+                                    if (filter.filterType === 'raftSession' ||
+                                        (filter.filterType === 'bucket' &&
+                                         seqs[i].db === filter.bucket.bucketName)) {
+                                        for (let j = 0; j < seqs[i].entries.length; j++) {
+                                            const _item = {};
+                                            _item.bucketName = seqs[i].db;
+                                            _item.key = seqs[i].entries[j].key;
+                                            if (seqs[i].entries[j].type !== undefined &&
+                                                seqs[i].entries[j].type === 'del') {
+                                                if (!isMasterKey(_item.key)) {
+                                                    // ignore for now
+                                                    return;
+                                                }
+                                                delQueue.push(_item);
+                                            } else {
+                                                _item.value = Object.assign({}, seqs[i].entries[j].value);
+                                                addQueue.push(_item);
+                                            }
+                                        }
+                                    }
+                                }
+                                this.persistData.updateState(
+                                    addQueue, delQueue, err => {
+                                        if (err) {
+                                            return _next(err);
+                                        }
+                                        _cseq += seqs.length;
+                                        this.persist.save(
+                                            filterName, this.persistData, _cseq, err => {
+                                                if (err) {
+                                                    return _next(err);
+                                                }
+                                                if (_cseq > this.stopAt) {
+                                                    doStop = true;
+                                                }
+                                                return _next();
+                                            });
+                                        return undefined;
+                                    });
+                            });
+                            return undefined;
+                        });
+                    }, err => {
+                        if (err) {
+                            return nextOnce(err);
+                        }
+                        return nextOnce();
+                    });
+            },
+        ], err => {
+            if (err) {
+                return cb(err);
+            }
+            this.logger.info('returning',
+                             { filterName });
+            return cb();
+        });
+        return undefined;
+    }
+}
+
+module.exports = BucketdOplogInterface;
diff --git a/lib/storage/metadata/oplog/MongoOplogInterface.js b/lib/storage/metadata/oplog/MongoOplogInterface.js
new file mode 100644
index 000000000..a5369b4fd
--- /dev/null
+++ b/lib/storage/metadata/oplog/MongoOplogInterface.js
@@ -0,0 +1,163 @@
+/*
+ * Main interface for Mongo oplog management
+ */
+const MongoClient = require('mongodb').MongoClient;
+const bson = require('bson');
+const { jsutil, errors } = require('arsenal');
+const async = require('async');
+const { isMasterKey } = require('arsenal/lib/versioning/Version');
+const OplogInterface = require('./OplogInterface');
+
+class MongoOplogInterface extends OplogInterface {
+
+    constructor(params) {
+        super(params);
+        this.mongoDbUri = 'mongodb://localhost:27017';
+        if (params && params.mongoDbUri !== undefined) {
+            this.mongoDbUri = params.mongoDbUri;
+        }
+        this.databaseName = 'metadata';
+        if (params && params.databaseName !== undefined) {
+            this.databaseName = params.databaseName;
+        }
+    }
+
+    start(filter, cb) {
+        if (filter.filterType !== 'bucket') {
+            return cb(errors.NotImplemented);
+        }
+        const filterName = filter.filterName;
+        const bucketName = filter.bucket.bucketName;
+        let db;
+        let collection;
+        async.waterfall([
+            /*
+             * In this step we connect to MongoDB
+             */
+            next => {
+                MongoClient.connect(
+                    this.mongoDbUri,
+                    (err, client) => {
+                        if (err) {
+                            this.logger.error('error connecting to mongodb', { err, filterName });
+                            return next(err);
+                        }
+                        db = client.db(this.databaseName, {
+                            ignoreUndefined: true,
+                        });
+                        collection = db.collection(bucketName);
+                        return next();
+                    });
+            },
+            /*
+             * In this step we get the stored offset if we have it
+             */
+            next => {
+                let resumeToken = undefined;
+                this.persist.load(filterName, this.persistData, (err, offset) => {
+                    if (err) {
+                        return next(err);
+                    }
+                    if (offset && offset._data) {
+                        resumeToken = {};
+                        resumeToken._data = new bson.Binary(Buffer.from(offset._data, 'base64'));
+                    }
+                    return next(null, resumeToken);
+                });
+            },
+            /*
+             * In this step we acquire the offset if we don't already have it
+             */
+            (resumeToken, next) => {
+                if (resumeToken !== undefined) {
+                    this.logger.info(
+                        `skipping resumeToken acquisition (resumeToken=${resumeToken})`,
+                        { filterName });
+                    return next(null, resumeToken, true);
+                }
+                this.logger.info('resumeToken acquisition',
+                                 { filterName });
+                const changeStream = collection.watch();
+                // big hack to extract resumeToken
+                changeStream.once('change', () => next(null, changeStream.resumeToken, false));
+                return undefined;
+            },
+            /*
+             * In this step we init the state (e.g. scan)
+             */
+            (resumeToken, skipInit, next) => {
+                if (skipInit) {
+                    this.logger.info(`skipping state initialization resumeToken=${resumeToken}`,
+                                     { filterName });
+                    return next(null, resumeToken);
+                }
+                this.logger.info(`initializing state resumeToken=${resumeToken}`,
+                                 { filterName });
+                this.persistData.initState(
+                    err => {
+                        if (err) {
+                            // eslint-disable-next-line
+                            console.error(err);
+                            process.exit(1);
+                        }
+                        this.persist.save(
+                            filterName, this.persistData, resumeToken, err => {
+                                if (err) {
+                                    return next(err);
+                                }
+                                return next(null, resumeToken);
+                            });
+                        return undefined;
+                    });
+                return undefined;
+            },
+            /*
+             * In this step we loop over the oplog
+             */
+            (resumeToken, next) => {
+                this.logger.info(`reading oplog resumeToken=${resumeToken}`,
+                                 { filterName });
+                // only way to get out of the loop in all cases
+                const nextOnce = jsutil.once(next);
+                // read the change stream
+                const changeStream = collection.watch({ resumeAfter: resumeToken });
+                // start bufferization
+                this.filterName = filterName;
+                this.startFlusher();
+                changeStream.on(
+                    'change', item => {
+                        if (item.ns.db === this.databaseName) {
+                            const _item = {};
+                            _item.bucketName = bucketName;
+                            _item.key = item.documentKey._id;
+                            if (item.operationType === 'insert' ||
+                                item.operationType === 'replace') {
+                                _item.value = Object.assign({}, item.fullDocument.value);
+                                this.addEvent(_item, changeStream.resumeToken);
+                            } else if (item.operationType === 'delete') {
+                                if (!isMasterKey(_item.key)) {
+                                    // ignore for now
+                                    return;
+                                }
+                                this.delEvent(_item, changeStream.resumeToken);
+                            } else if (item.operationType === 'invalidate') {
+                                nextOnce();
+                                return;
+                            } else {
+                                return;
+                            }
+                        }
+                    });
+            }], err => {
+            if (err) {
+                return cb(err);
+            }
+            this.logger.info('returning',
+                             { filterName });
+            return cb();
+        });
+        return undefined;
+    }
+}
+
+module.exports = MongoOplogInterface;
diff --git a/lib/storage/metadata/oplog/OplogInterface.js b/lib/storage/metadata/oplog/OplogInterface.js
new file mode 100644
index 000000000..81b28d638
--- /dev/null
+++ b/lib/storage/metadata/oplog/OplogInterface.js
@@ -0,0 +1,138 @@
+/*
+ * Interface for oplog management
+ *
+ * filter is an object with the following structure: {
+ *           filterName: string,
+ *           filterType: bucket|bucketList|raftSession,
+ *           bucket: {
+ *               bucketName: string,
+ *           },
+ *           bucketList: {
+ *               bucketList: [string, ...]
+ *           },
+ *           raftSession: {
+ *               raftId: number,
+ *           },
+ *       }
+ *
+ * persist is an interface with the following methods:
+ * - constructor(params)
+ * - load(filterName, persistData, cb(err, offset))
+ * - save(filterName, persistData, offset, cb(err))
+
+ * persistData is an interface with the following methods:
+ * - constuctor(params)
+ * - initState(cb(err)): initialize the structure, e.g. initial bucket scan
+ * - loadState(stream, cb(err)): load the state
+ * - saveState(stream, cb(err)): save the state
+ * - updateState(addQueue, delQueue, cb(err)): update the state
+ *               item: { filterName, key, value }
+ */
+const werelogs = require('werelogs');
+
+werelogs.configure({
+    level: 'info',
+    dump: 'error',
+});
+
+class OplogInterface {
+
+    constructor(params) {
+        this.persist = params?.persist;
+        this.persistData = params?.persistData;
+        this.logger = new werelogs.Logger('OplogInterface');
+        /* for backends requiring bufferization only */
+        this.bufferTimeoutMs = params?.bufferTimeoutMs ?? 500;
+        this.addQueue = [];
+        this.delQueue = [];
+        this.pending = false;
+        this.prevOffset = null;
+        this.offset = null;
+    }
+
+    addEvent(item, offset) {
+        this.addQueue.push(item);
+        this.offset = offset;
+    }
+
+    delEvent(item, offset) {
+        this.delQueue.push(item);
+        this.offset = offset;
+    }
+
+    /*
+     * Optional buffer management for backends that don't bufferize.
+     * It avoids persisting the state at each event
+     */
+    flushQueue(cb) {
+        if (this.offset === null ||
+            this.prevOffset === this.offset) {
+            if (cb) {
+                return process.nextTick(cb);
+            }
+            return undefined;
+        }
+        if (this.pending) {
+            if (cb) {
+                return process.nextTick(cb);
+            }
+            return undefined;
+        }
+        this.pending = true;
+        const addQueue = this.addQueue;
+        this.addQueue = [];
+        const delQueue = this.delQueue;
+        this.delQueue = [];
+        const offset = this.offset;
+        this.prevOffset = this.offset;
+        this.persistData.updateState(
+            addQueue,
+            delQueue,
+            err => {
+                if (err) {
+                    if (cb) {
+                        return cb(err);
+                    }
+                }
+                this.persist.save(
+                    this.filterName,
+                    this.persistData,
+                    offset,
+                    err => {
+                        this.pending = false;
+                        if (err) {
+                            if (cb) {
+                                return cb(err);
+                            }
+                            return undefined;
+                        }
+                        if (cb) {
+                            return cb();
+                        }
+                        return undefined;
+                    });
+                return undefined;
+            });
+        return undefined;
+    }
+
+    doFlush() {
+        this.flushQueue(err => {
+            if (err) {
+                this.logger.error('flusing buffer', { err });
+            }
+        });
+        this.startFlusher();
+    }
+
+    startFlusher() {
+        setTimeout(this.doFlush.bind(this), this.bufferTimeoutMs);
+    }
+
+    // method to be overridden
+    start() {
+        throw new Error('not implemented');
+    }
+}
+
+module.exports = OplogInterface;
diff --git a/lib/storage/metadata/oplog/PersistFileInterface.js b/lib/storage/metadata/oplog/PersistFileInterface.js
new file mode 100644
index 000000000..4a5ca2f59
--- /dev/null
+++ b/lib/storage/metadata/oplog/PersistFileInterface.js
@@ -0,0 +1,91 @@
+const fs = require('fs');
+const werelogs = require('werelogs');
+
+werelogs.configure({
+    level: 'info',
+    dump: 'error',
+});
+
+class PersistFileInterface {
+
+    constructor() {
+        this.folder = '/tmp';
+        this.logger = new werelogs.Logger('PersistFileInterface');
+        fs.access(this.folder, err => {
+            if (err) {
+                fs.mkdirSync(this.folder, { recursive: true });
+            }
+        });
+    }
+
+    getFileName(filterName) {
+        return `${this.folder}/${filterName}.json`;
+    }
+
+    getOffsetFileName(filterName) {
+        return `${this.folder}/${filterName}.offset.json`;
+    }
+
+    load(filterName, persistData, cb) {
+        const fileName = this.getFileName(filterName);
+        const offsetFileName = this.getOffsetFileName(filterName);
+        let obj = {};
+        fs.readFile(
+            offsetFileName,
+            'utf-8', (err, data) => {
+                if (err) {
+                    if (err.code === 'ENOENT') {
+                        this.logger.info(`${offsetFileName} non-existent`);
+                    } else {
+                        this.logger.error('error loading', { err });
+                        return cb(err);
+                    }
+                } else {
+                    obj = JSON.parse(data);
+                }
+                if (fs.existsSync(fileName)) {
+                    const file = fs.createReadStream(fileName);
+                    persistData.loadState(file, err => {
+                        if (err) {
+                            return cb(err);
+                        }
+                        this.logger.info(`${fileName} loaded: offset ${obj.offset}`);
+                        return cb(null, obj.offset);
+                    });
+                } else {
+                    this.logger.info(`${fileName} non-existent`);
+                    return cb(null, obj.offset);
+                }
+                return undefined;
+            });
+    }
+
+    save(filterName, persistData, offset, cb) {
+        const fileName = this.getFileName(filterName);
+        const offsetFileName = this.getOffsetFileName(filterName);
+        const file = fs.createWriteStream(fileName);
+        persistData.saveState(file, err => {
+            if (err) {
+                return cb(err);
+            }
+            const obj = {
+                offset,
+            };
+            fs.writeFile(
+                offsetFileName, JSON.stringify(obj),
+                'utf-8',
+                err => {
+                    if (err) {
+                        this.logger.error('error saving', { err });
+                        return cb(err);
+                    }
+                    this.logger.info(`${fileName} saved: offset ${offset}`);
+                    return cb();
+                });
+            return undefined;
+        });
+        return undefined;
+    }
+}
+
+module.exports = PersistFileInterface;
diff --git a/lib/storage/metadata/oplog/PersistMemInterface.js b/lib/storage/metadata/oplog/PersistMemInterface.js
new file mode 100644
index 000000000..747f16e6a
--- /dev/null
+++ b/lib/storage/metadata/oplog/PersistMemInterface.js
@@ -0,0 +1,73 @@
+// fake backend for unit tests
+const assert = require('assert');
+const MemoryStream = require('memorystream');
+const werelogs = require('werelogs');
+
+werelogs.configure({
+    level: 'info',
+    dump: 'error',
+});
+
+class PersistMemInterface {
+
+    constructor() {
+        this.memoryStreams = {};
+        this.offsets = {};
+        this.logger = new werelogs.Logger('PersistMemInterface');
+    }
+
+    getOffset(filterName) {
+        if (!this.offsets[filterName]) {
+            return {};
+        }
+        return this.offsets[filterName];
+    }
+
+    setOffset(filterName, offset) {
+        if (!this.memoryStreams[filterName]) {
+            this.memoryStreams[filterName] = new MemoryStream();
+        }
+        if (!this.offsets[filterName]) {
+            this.offsets[filterName] = {};
+        }
+        Object.assign(
+            this.offsets[filterName],
+            offset);
+    }
+
+    load(filterName, persistData, cb) {
+        this.logger.info(`loading ${filterName}`);
+        const stream = this.memoryStreams[filterName];
+        const offset = this.offsets[filterName];
+        if (stream === undefined) {
+            this.logger.info(`${filterName} non-existent`);
+            return cb(null, undefined);
+        }
+        assert(offset !== undefined);
+        persistData.loadState(stream, err => {
+            if (err) {
+                return cb(err);
+            }
+            this.logger.info(`${filterName} loaded: offset ${offset}`);
+            return cb(null, offset);
+        });
+        return undefined;
+    }
+
+    save(filterName, persistData, offset, cb) {
+        this.logger.info(`saving ${filterName} offset ${JSON.stringify(offset)}`);
+        const stream = new MemoryStream();
+        this.memoryStreams[filterName] = stream;
+        persistData.saveState(stream, err => {
+            if (err) {
+                return cb(err);
+            }
+            this.offsets[filterName] = offset;
+            this.logger.info(`${filterName} saved: offset ${offset}`);
+            return cb();
+        });
+    }
+}
+
+module.exports = PersistMemInterface;
+
diff --git a/lib/storage/metadata/oplog/PersistRingInterface.js b/lib/storage/metadata/oplog/PersistRingInterface.js
new file mode 100644
index 000000000..8e1961108
--- /dev/null
+++ b/lib/storage/metadata/oplog/PersistRingInterface.js
@@ -0,0 +1,283 @@
+// Ring backend that persists on Sproxyd and offsets on ZK
+const async = require('async');
+const { pipeline } = require('stream');
+const MemoryStream = require('memorystream');
+const zlib = require('zlib');
+const zookeeper = require('node-zookeeper-client');
+const Sproxy = require('sproxydclient');
+const werelogs = require('werelogs');
+
+werelogs.configure({
+    level: 'info',
+    dump: 'error',
+});
+
+class PersistRingInterface {
+
+    constructor(params) {
+        let zkConnectionString = 'localhost:2181';
+        if (params && params.zkConnectionString !== undefined) {
+            zkConnectionString = params.zkConnectionString;
+        }
+        this.zkPath = '/persist-ring-interface';
+        if (params && params.zkPath !== undefined) {
+            this.zkPath = params.zkPath;
+        }
+        let spPath = '/proxy/DC1/'; // do not forget "/" at the end !!!
+        if (params && params.spPath !== undefined) {
+            spPath = params.spPath;
+        }
+        let spBootstrap = ['localhost:8181'];
+        if (params && params.spBootstrap !== undefined) {
+            spBootstrap = params.spBootstrap;
+        }
+        this.reqUid = 'persist-ring-interface-req-uid';
+        this.logger = new werelogs.Logger('PersistRingInterface');
+        this.zkClient = zookeeper.createClient(zkConnectionString);
+        this.zkClient.connect();
+        this.zkClient.on('error', err => {
+            this.logger.error('error connecting', { err });
+        });
+        this.zkClient.once('connected', () => {
+            this.logger.info('connected');
+        });
+        this.spClient = new Sproxy({
+            bootstrap: spBootstrap,
+            path: spPath,
+        });
+    }
+
+    getZKPath(filterName) {
+        return `${this.zkPath}/${filterName}`;
+    }
+
+    load(filterName, persistData, cb) {
+        this.logger.info(`loading ${filterName}`);
+        async.waterfall([
+            /*
+             * Check of we have an existing Zookeeper node
+             */
+            next => {
+                this.zkClient.getData(
+                    this.getZKPath(filterName),
+                    (err, data) => {
+                        if (err) {
+                            if (err.name === 'NO_NODE') {
+                                this.logger.info(`${filterName} non-existent`);
+                            } else {
+                                this.logger.error(`getData ${filterName} error`, { err });
+                            }
+                            return next(err);
+                        }
+                        return next(null, data);
+                    });
+            },
+            /*
+             * Extract the Sproxyd key from the Zookeeper node.
+             * Read the key from Sproxyd.
+             */
+            (data, next) => {
+                const _data = JSON.parse(data.toString());
+                this.spClient.get(
+                    _data.key,
+                    undefined,
+                    this.reqUid,
+                    (err, stream) => {
+                        if (err) {
+                            this.logger.error(`sproxyd ${filterName} error`, { err });
+                            return next(err);
+                        }
+                        return next(null, _data, stream);
+                    });
+            },
+            /*
+             * Uncompress the stream in memory
+             */
+            (_data, stream, next) => {
+                const ostream = new MemoryStream();
+                pipeline(
+                    stream,
+                    zlib.createGunzip(),
+                    ostream,
+                    err => {
+                        if (err) {
+                            this.logger.error(`pipeline ${filterName} error`, { err });
+                            return next(err);
+                        }
+                        return next(null, _data, ostream);
+                    });
+            },
+            /*
+             * Load the state from uncompressed stream
+             */
+            (_data, stream, next) => {
+                persistData.loadState(stream, err => {
+                    if (err) {
+                        this.logger.error(`load ${filterName} error`, { err });
+                        return next(err);
+                    }
+                    this.logger.info(`${filterName} loaded: offset ${_data.offset}`);
+                    return next(null, _data);
+                });
+            }], (err, _data) => {
+            if (err) {
+                if (err.name === 'NO_NODE') {
+                    return cb(null, undefined);
+                }
+                this.logger.error(`load ${filterName} error`, { err });
+                return cb(err);
+            }
+            return cb(null, _data.offset);
+        });
+    }
+
+    save(filterName, persistData, offset, cb) {
+        this.logger.info(`saving ${filterName} offset ${offset}`);
+        async.waterfall([
+            /*
+             * Save the state in a memory stream
+             */
+            next => {
+                const stream = new MemoryStream();
+                persistData.saveState(
+                    stream, err => {
+                        if (err) {
+                            this.logger.error(`save ${filterName} error`, { err });
+                            return next(err);
+                        }
+                        return next(null, stream);
+                    });
+            },
+            /*
+             * Compress the state in memory
+             */
+            (stream, next) => {
+                const ostream = new MemoryStream();
+                pipeline(
+                    stream,
+                    zlib.createGzip(),
+                    ostream,
+                    err => {
+                        if (err) {
+                            this.logger.error(`pipeline ${filterName} error`, { err });
+                            return next(err);
+                        }
+                        return next(null, ostream);
+                    });
+            },
+            /*
+             * Store the state in Sproxyd
+             */
+            (stream, next) => {
+                const parameters = {
+                    filterName,
+                    namespace: 'persist-ring-interface',
+                    owner: 'persist-ring-interface',
+                };
+                const size = stream._readableState.length;
+                this.spClient.put(
+                    stream,
+                    size,
+                    parameters,
+                    this.reqUid,
+                    (err, key) => {
+                        if (err) {
+                            this.logger.error(`sproxyd put ${filterName} error`, { err });
+                            return next(err);
+                        }
+                        const newData = {};
+                        newData.offset = offset;
+                        newData.key = key;
+                        return next(null, newData);
+                    });
+            },
+            /*
+             * Check if the Zookeeper node exists
+             */
+            (newData, next) => {
+                this.zkClient.exists(
+                    this.getZKPath(filterName),
+                    (err, stat) => {
+                        if (err) {
+                            this.logger.error(`exists ${filterName} error`, { err });
+                            return next(err);
+                        }
+                        let doesExist = false;
+                        if (stat) {
+                            doesExist = true;
+                        }
+                        return next(null, newData, doesExist);
+                    });
+            },
+            /*
+             * If the Zookeeper node exists read it.
+             * Else create it.
+             */
+            (newData, doesExist, next) => {
+                if (doesExist) {
+                    this.zkClient.getData(
+                        this.getZKPath(filterName),
+                        (err, _oldData) => {
+                            if (err) {
+                                this.logger.error(`getData ${filterName} error`, { err });
+                                return next(err);
+                            }
+                            const oldData = JSON.parse(_oldData);
+                            return next(null, newData, oldData);
+                        });
+                } else {
+                    this.zkClient.mkdirp(
+                        this.getZKPath(filterName),
+                        null,
+                        err => {
+                            if (err) {
+                                this.logger.error(`mkdirp ${filterName} error`, { err });
+                                return next(err);
+                            }
+                            return next(null, newData, null);
+                        });
+                }
+            },
+            /*
+             * Store the context in the Zookeeper node and delete the old sproxyd key.
+             */
+            (newData, oldData, next) => {
+                const _newData = JSON.stringify(newData);
+                this.zkClient.setData(
+                    this.getZKPath(filterName),
+                    Buffer.from(_newData),
+                    err => {
+                        if (err) {
+                            this.logger.error(`setData ${filterName} error`, { err });
+                            return cb(err);
+                        }
+                        this.logger.info(`${filterName} saved: new key ${newData.key} offset ${offset}`);
+                        if (oldData) {
+                            this.spClient.delete(
+                                oldData.key,
+                                this.reqUid,
+                                err => {
+                                    if (err) {
+                                        this.logger.error(
+                                            `sproxyd del ${filterName} old key ${oldData.key} error`,
+                                            { err });
+                                        return next(err);
+                                    }
+                                    return next();
+                                });
+                        } else {
+                            return next();
+                        }
+                        return undefined;
+                    });
+            }], err => {
+            if (err) {
+                this.logger.error(`save ${filterName} error`, { err });
+                return cb(err);
+            }
+            return cb();
+        });
+    }
+}
+
+module.exports = PersistRingInterface;
diff --git a/package.json b/package.json
index da91d5e7a..36b66c05f 100644
--- a/package.json
+++ b/package.json
@@ -3,7 +3,7 @@
   "engines": {
     "node": ">=16"
   },
-  "version": "7.10.13",
+  "version": "7.10.14",
   "description": "Common utilities for the S3 project components",
   "main": "build/index.js",
   "repository": {
@@ -36,8 +36,10 @@
     "ipaddr.js": "1.9.1",
     "level": "~5.0.1",
     "level-sublevel": "~6.6.5",
+    "memorystream": "^0.3.1",
     "mongodb": "^3.0.1",
     "node-forge": "^0.7.1",
+    "node-zookeeper-client": "^0.2.2",
     "prom-client": "10.2.3",
     "simple-glob": "^0.2",
     "socket.io": "~2.3.0",
@@ -57,6 +59,7 @@
     "@sinonjs/fake-timers": "^6.0.1",
     "@types/jest": "^27.4.1",
     "@types/node": "^17.0.21",
+    "argparse": "^2.0.1",
     "eslint": "2.13.1",
     "eslint-config-airbnb": "6.2.0",
     "eslint-config-scality": "scality/Guidelines#7.10.2",
@@ -64,6 +67,7 @@
     "jest": "^27.5.1",
     "mocha": "8.0.1",
     "mongodb-memory-server": "^6.0.2",
+    "prando": "^6.0.1",
     "sinon": "^9.0.2",
     "temp": "0.9.1",
     "ts-jest": "^27.1.3",
diff --git a/tests/unit/storage/metadata/FakeBucketInfo.json b/tests/unit/storage/metadata/FakeBucketInfo.json
new file mode 100644
index 000000000..8f738f2cf
--- /dev/null
+++ b/tests/unit/storage/metadata/FakeBucketInfo.json
@@ -0,0 +1,26 @@
+{
+    "acl": {
+        "Canned": "private",
+        "FULL_CONTROL": [],
+        "WRITE": [],
+        "WRITE_ACP": [],
+        "READ": [],
+        "READ_ACP": []
+    },
+    "name": "BucketName",
+    "owner": "9d8fe19a78974c56dceb2ea4a8f01ed0f5fecb9d29f80e9e3b84104e4a3ea520",
+    "ownerDisplayName": "anonymousCoward",
+    "creationDate": "2018-06-04T17:45:42.592Z",
+    "mdBucketModelVersion": 8,
+    "transient": false,
+    "deleted": false,
+    "serverSideEncryption": null,
+    "versioningConfiguration": null,
+    "websiteConfiguration": null,
+    "locationConstraint": "us-east-1",
+    "readLocationConstraint": "us-east-1",
+    "cors": null,
+    "replicationConfiguration": null,
+    "lifecycleConfiguration": null,
+    "uid": "fea97818-6a9a-11e8-9777-e311618cc5d4"
+}
diff --git a/tests/unit/storage/metadata/Injector.js b/tests/unit/storage/metadata/Injector.js
new file mode 100644
index 000000000..a827bfd7c
--- /dev/null
+++ b/tests/unit/storage/metadata/Injector.js
@@ -0,0 +1,268 @@
+const async = require('async');
+const assert = require('assert');
+const Prando = require('prando');
+const werelogs = require('werelogs');
+const MetadataWrapper = require('../../../../lib/storage/metadata/MetadataWrapper');
+const fakeBucketInfo = require('./FakeBucketInfo.json');
+
+werelogs.configure({
+    level: 'info',
+    dump: 'error',
+});
+
+class Injector {
+
+    /**
+     * @constructor
+     *
+     * @param {Object} backend - Metadata backend to use for injection
+     * @param {Object} logger - Logger to use
+     */
+    constructor(backend, logger) {
+        this.backend = backend;
+        this.rnd = new Prando(0);
+        this.logger = logger;
+    }
+
+    get opPut() {
+        return 1;
+    }
+
+    get opDelete() {
+        return 0;
+    }
+
+    genKey(len) {
+        const characters =
+              'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
+        return this.rnd.nextString(len, characters);
+    }
+
+    genBase16(len) {
+        const characters = 'abcdef0123456789';
+        return this.rnd.nextString(len, characters);
+    }
+
+    _zeroPad(s, n, width) {
+        return s + n.toString().padStart(width, '0');
+    }
+
+    /**
+     * Deterministic injection of puts or deletes according to parameters
+     *
+     * @param {String} bucketName - bucket name to inject to
+     * @param {Object} params - parameters for injection
+     * @param {Array} inputKeys - optional keys to use as input
+     * @param {Array} outputKeys - optional generated keys as output
+     * @param {Array} outputValues - optional generated values as output
+     * @param {function} cb - callback when done
+     *
+     * @return {undefined}
+     */
+    inject(bucketName, params, inputKeys, outputKeys, outputValues, cb) {
+        let maxKeyLen = 1024;
+        if (params.maxKeyLen !== undefined) {
+            maxKeyLen = params.maxKeyLen;
+        }
+        async.timesLimit(
+            params.numKeys,
+            10,
+            (n, next) => {
+                let key;
+                if (inputKeys) {
+                    const idx = this.rnd.nextInt(0, inputKeys.length - 1);
+                    key = inputKeys[idx];
+                    inputKeys.splice(idx, 1);
+                } else {
+                    if (params.randomKey) {
+                        const len = this.rnd.nextInt(1, maxKeyLen);
+                        key = this.genKey(len);
+                    } else {
+                        let x;
+                        if (params.randomSeq) {
+                            x = this.rnd.nextInt(0, params.maxSeq - 1);
+                        } else {
+                            x = n;
+                        }
+                        key = this._zeroPad(params.prefix, x, 10) +
+                            params.suffix;
+                    }
+                }
+                if (outputKeys) {
+                    outputKeys.push(key);
+                }
+                // eslint-disable-next-line
+                const value = {
+                    versionId: this.genBase16(32),
+                    'content-length': this.rnd.nextInt(0, 5000000),
+                    'content-md5': this.genBase16(32),
+                };
+                if (outputValues) {
+                    outputValues.push(value);
+                }
+                if (params.op === this.opPut) {
+                    this.backend.putObjectMD(
+                        bucketName,
+                        key,
+                        value,
+                        {},
+                        this.logger,
+                        next);
+                    return undefined;
+                } else if (params.op === this.opDelete) {
+                    this.backend.deleteObjectMD(
+                        bucketName,
+                        key,
+                        {},
+                        this.logger,
+                        err => {
+                            if (err) {
+                                if (err.code !== 404) {
+                                    return next(err);
+                                }
+                            }
+                            return next();
+                        });
+                    return undefined;
+                }
+                return next(new Error('unknow op'));
+            },
+            err => {
+                if (err) {
+                    // eslint-disable-next-line
+                    console.error('inject error', err);
+                    process.exit(1);
+                }
+                if (cb) {
+                    return cb();
+                }
+                return undefined;
+            });
+    }
+}
+
+module.exports = Injector;
+
+describe('Injector', () => {
+    const fakeBucket = 'fake';
+    const logger = new werelogs.Logger('Injector');
+    const memBackend = new MetadataWrapper(
+        'mem', {}, null, logger);
+
+    before(done => {
+        memBackend.createBucket(fakeBucket, fakeBucketInfo, logger, done);
+    });
+
+    after(done => {
+        memBackend.deleteBucket(fakeBucket, logger, done);
+    });
+
+    it('zeropad', () => {
+        const injector = new Injector(memBackend, logger);
+        assert(injector._zeroPad('foo', 42, 10) === 'foo0000000042');
+    });
+
+    it('inject inputKeys', done => {
+        const injector = new Injector(memBackend, logger);
+        const inputKeys = ['foo1', 'foo2', 'foo3'];
+        const outputKeys = [];
+        injector.inject(
+            fakeBucket,
+            {
+                op: injector.opPut,
+                numKeys: 3,
+            },
+            inputKeys,
+            outputKeys,
+            null,
+            err => {
+                if (err) {
+                    return done(err);
+                }
+                assert.deepEqual(outputKeys, ['foo2', 'foo1', 'foo3']);
+                return done();
+            });
+    });
+
+    it('inject sequence', done => {
+        const injector = new Injector(memBackend, logger);
+        const outputKeys = [];
+        injector.inject(
+            fakeBucket,
+            {
+                prefix: 'foo',
+                suffix: 'x',
+                randomSeq: true,
+                maxSeq: 10,
+                op: injector.opPut,
+                numKeys: 3,
+            },
+            null,
+            outputKeys,
+            null,
+            err => {
+                if (err) {
+                    return done(err);
+                }
+                assert.deepEqual(
+                    outputKeys,
+                    [
+                        'foo0000000005x',
+                        'foo0000000001x',
+                        'foo0000000000x',
+                    ]);
+                return done();
+            });
+    });
+
+    it('inject random', done => {
+        const injector = new Injector(memBackend, logger);
+        const outputKeys = [];
+        const outputValues = [];
+        injector.inject(
+            fakeBucket,
+            {
+                prefix: 'foo',
+                suffix: 'x',
+                randomKey: true,
+                maxKeyLen: 10,
+                op: injector.opPut,
+                numKeys: 3,
+            },
+            null,
+            outputKeys,
+            outputValues,
+            err => {
+                if (err) {
+                    return done(err);
+                }
+                assert.deepEqual(
+                    outputKeys,
+                    [
+                        'f5TJ6X',
+                        '7T',
+                        'LStNJxHS8',
+                    ]);
+                assert.deepEqual(
+                    outputValues,
+                    [
+                        {
+                            'content-length': 3009012,
+                            'content-md5': '60f7abfdc5855e00a6e6dc2918bda7a8',
+                            'versionId': 'f13938435117885f7f88d7636a3b238e',
+                        },
+                        {
+                            'content-length': 3984521,
+                            'content-md5': '7cfc7e8b82826b83e302d18fa0e24b12',
+                            'versionId': 'f7f5c4973bc353ad8a9d5084fc1f0dc3',
+                        },
+                        {
+                            'content-length': 4112702,
+                            'content-md5': '6d4fe78b11cfa4ff7b2efaba5c5965fe',
+                            'versionId': '5540954e05a7910abeb72b8393c93afe',
+                        },
+                    ]);
+                return done();
+            });
+    });
+});
diff --git a/tests/unit/storage/metadata/oplog/BucketdOplogInterface.js b/tests/unit/storage/metadata/oplog/BucketdOplogInterface.js
new file mode 100644
index 000000000..0ef3e0a6f
--- /dev/null
+++ b/tests/unit/storage/metadata/oplog/BucketdOplogInterface.js
@@ -0,0 +1,216 @@
+const async = require('async');
+const fakeBucketInfo = require('../FakeBucketInfo.json');
+const MetadataWrapper = require('../../../../../lib/storage/metadata/MetadataWrapper');
+const BucketdOplogInterface = require('../../../../../lib/storage/metadata/oplog/BucketdOplogInterface');
+const PersistMemInterface = require('../../../../../lib/storage/metadata/oplog/PersistMemInterface');
+const Injector = require('../Injector');
+const http = require('http');
+const url = require('url');
+const werelogs = require('werelogs');
+
+werelogs.configure({
+    level: 'info',
+    dump: 'error',
+});
+
+class PersistDataInterface {
+
+    constructor() {
+        this.data = null;
+    }
+
+    initState(cb) {
+        this.data = {};
+        return process.nextTick(cb);
+    }
+
+    loadState(stream, cb) {
+        const chunks = [];
+        stream.on('data', chunk => {
+            chunks.push(chunk);
+        });
+        stream.on('end', () => {
+            this.data = JSON.parse(Buffer.concat(chunks));
+            return process.nextTick(cb);
+        });
+    }
+
+    saveState(stream, cb) {
+        stream.write(JSON.stringify(this.data));
+        stream.end();
+        return process.nextTick(cb);
+    }
+
+    updateState(addQueue, deleteQueue, cb) {
+        return process.nextTick(cb);
+    }
+}
+
+describe('BucketdOplogInterface', () => {
+    const logger = new werelogs.Logger('BucketOplogInterface');
+
+    const fakePort = 9090;
+    const fakeBucket = 'fake';
+    const fakeRaftId = 2;
+    const numObjs = 20000;
+    const fakeCseq = 20001;
+    let oplogInjected = false;
+    const numOplogSeqs = 100;
+    const oplogBatchSize = 2;
+    const endCseq = fakeCseq + numOplogSeqs;
+    const maxLimit = 2;
+    const oplogKeys = [];
+    const oplogValues = [];
+    let oplogKeysIdx = 0;
+
+    const memBackend = new MetadataWrapper(
+        'mem', {}, null, logger);
+    const injector = new Injector(memBackend, logger);
+
+    const requestListener = (req, res) => {
+        const _url = url.parse(req.url, true);
+        if (_url.pathname === `/_/buckets/${fakeBucket}`) {
+            res.writeHead(200);
+            res.end(JSON.stringify(
+                {
+                    raftSessionId: fakeRaftId,
+                    creating: false,
+                    deleting: false,
+                    version: 0,
+                }));
+        } else if (_url.pathname === `/_/raft_sessions/${fakeRaftId}/log`) {
+            const begin = _url.query.begin;
+            const limit = _url.query.limit;
+            if (begin === '1' && limit === '1') {
+                res.writeHead(200);
+                res.end(JSON.stringify(
+                    {
+                        info: {
+                            start: 1,
+                            cseq: fakeCseq,
+                            prune: 1,
+                        },
+                    }));
+            } else {
+                const realLimit = Math.min(limit, maxLimit);
+                async.until(
+                    () => oplogInjected,
+                    next => {
+                        // inject similar but different random objects
+                        injector.inject(
+                            fakeBucket,
+                            {
+                                numKeys: numOplogSeqs * oplogBatchSize,
+                                maxSeq: numObjs,
+                                op: injector.opPut,
+                                randomSeq: true,
+                                prefix: 'obj_',
+                                suffix: '_bis',
+                            },
+                            null,
+                            oplogKeys,
+                            oplogValues,
+                            err => {
+                                if (err) {
+                                    return next(err);
+                                }
+                                oplogInjected = true;
+                                return next();
+                            });
+                    }, err => {
+                        if (err) {
+                            res.writeHead(404);
+                            res.end('error', err);
+                            return undefined;
+                        }
+                        if (begin < endCseq) {
+                            res.writeHead(200);
+                            const resp = {};
+                            resp.info = {
+                                start: begin,
+                                cseq: endCseq,
+                                prune: 1,
+                            };
+                            resp.log = [];
+                            for (let i = 0; i < realLimit; i++) {
+                                resp.log[i] = {};
+                                resp.log[i].db = fakeBucket;
+                                resp.log[i].method = 8;
+                                resp.log[i].entries = [];
+                                for (let j = 0; j < oplogBatchSize; j++) {
+                                    resp.log[i].entries[j] = {};
+                                    resp.log[i].entries[j].key = oplogKeys[oplogKeysIdx];
+                                    resp.log[i].entries[j].value = oplogValues[oplogKeysIdx];
+                                    oplogKeysIdx++;
+                                }
+                            }
+                            res.end(JSON.stringify(resp));
+                        }
+                        return undefined;
+                    });
+            }
+        } else if (_url.pathname === `/default/bucket/${fakeBucket}`) {
+            const marker = _url.query.marker === '' ? null : _url.query.marker;
+            const maxKeys = parseInt(_url.query.maxKeys, 10);
+            memBackend.listObjects(fakeBucket, {
+                listingType: 'Delimiter',
+                marker,
+                maxKeys,
+            }, (err, result) => {
+                if (err) {
+                    res.writeHead(404);
+                    res.end('error', err);
+                    return undefined;
+                }
+                res.writeHead(200);
+                res.end(JSON.stringify(result));
+                return undefined;
+            });
+        }
+    };
+
+    before(done => {
+        const server = http.createServer(requestListener);
+        server.listen(fakePort);
+        async.waterfall([
+            next => memBackend.createBucket(fakeBucket, fakeBucketInfo, logger, next),
+            next => injector.inject(
+                fakeBucket,
+                {
+                    numKeys: numObjs,
+                    maxSeq: numObjs,
+                    op: injector.opPut,
+                    randomSeq: false,
+                    prefix: 'obj_',
+                    suffix: '',
+                },
+                null,
+                null,
+                null,
+                next),
+        ], done);
+    });
+
+    after(done => {
+        memBackend.deleteBucket(fakeBucket, logger, done);
+    });
+
+    it('simulation', done => {
+        const params = {
+            bootstrap: [`localhost:${fakePort}`],
+            persist: new PersistMemInterface(),
+            persistData: new PersistDataInterface(),
+            stopAt: numObjs + numOplogSeqs,
+        };
+        const bucketdOplog = new BucketdOplogInterface(params);
+        bucketdOplog.start(
+            {
+                filterName: fakeBucket,
+                filterType: 'bucket',
+                bucket: {
+                    bucketName: fakeBucket,
+                },
+            },
+            done);
+    });
+});
diff --git a/tests/unit/storage/metadata/oplog/PersistMem.js b/tests/unit/storage/metadata/oplog/PersistMem.js
new file mode 100644
index 000000000..078b386c2
--- /dev/null
+++ b/tests/unit/storage/metadata/oplog/PersistMem.js
@@ -0,0 +1,55 @@
+const assert = require('assert');
+const PersistMemInterface = require('../../../../../lib/storage/metadata/oplog/PersistMemInterface');
+
+class PersistDataInterface {
+
+    constructor(obj) {
+        this.obj = obj;
+    }
+
+    loadState(stream, cb) {
+        const chunks = [];
+        stream.on('data', chunk => {
+            chunks.push(chunk);
+        });
+        stream.on('end', () => {
+            this.obj = JSON.parse(Buffer.concat(chunks));
+            return cb();
+        });
+    }
+
+    saveState(stream, cb) {
+        stream.write(JSON.stringify(this.obj));
+        stream.end();
+        return cb();
+    }
+}
+
+describe('Persist Mem', () => {
+    const persist = new PersistMemInterface();
+    const filterName = 'foo';
+
+    it('basic operations', done => {
+        const pd1 = new PersistDataInterface({
+            foo: 'bar',
+            bar: {
+                qux: 42,
+                quuux: false,
+            },
+        });
+        const pd2 = new PersistDataInterface();
+        persist.save(filterName, pd1, 42, err => {
+            if (err) {
+                return done(err);
+            }
+            persist.load(filterName, pd2, err => {
+                if (err) {
+                    return done(err);
+                }
+                assert.deepEqual(pd1.obj, pd2.obj);
+                return done();
+            });
+            return undefined;
+        });
+    });
+});
diff --git a/tools/oplog-cli.js b/tools/oplog-cli.js
new file mode 100644
index 000000000..6a5aafea1
--- /dev/null
+++ b/tools/oplog-cli.js
@@ -0,0 +1,116 @@
+/* eslint-disable no-console */
+const fs = require('fs');
+const { ArgumentParser } = require('argparse');
+const BucketdOplogInterface = require('../lib/storage/metadata/oplog/BucketdOplogInterface');
+const MongoOplogInterface = require('../lib/storage/metadata/oplog/MongoOplogInterface');
+const PersistMemInterface = require('../lib/storage/metadata/oplog/PersistMemInterface');
+const PersistFileInterface = require('../lib/storage/metadata/oplog/PersistFileInterface');
+const PersistRingInterface = require('../lib/storage/metadata/oplog/PersistRingInterface');
+
+const parser = new ArgumentParser({
+    description: 'Oplog CLI tool',
+});
+
+parser.add_argument('-v', '--verbose', { action: 'store_true' });
+parser.add_argument('-c', '--config-file', { help: 'config file' });
+parser.add_argument('--oplog-interface', { help: 'bucketd|mongo' });
+parser.add_argument('--persist', { help: 'mem|file|ring' });
+parser.add_argument('--bucket', { help: 'bucket' });
+parser.add_argument('--start', { action: 'store_true' });
+
+const args = parser.parse_args();
+
+class PersistDataInterface {
+
+    constructor() {
+        this.data = null;
+    }
+
+    initState(cb) {
+        this.data = {};
+        return process.nextTick(cb);
+    }
+
+    loadState(stream, cb) {
+        const chunks = [];
+        stream.on('data', chunk => {
+            chunks.push(chunk);
+        });
+        stream.on('end', () => {
+            this.data = JSON.parse(Buffer.concat(chunks));
+            return process.nextTick(cb);
+        });
+    }
+
+    saveState(stream, cb) {
+        stream.write(JSON.stringify(this.data));
+        stream.end();
+        return process.nextTick(cb);
+    }
+
+    updateState(addQueue, deleteQueue, cb) {
+        console.log('addQueue', addQueue, 'deleteQueue', deleteQueue);
+        return process.nextTick(cb);
+    }
+}
+
+let config = {};
+
+if (args.config_file !== undefined) {
+    config = JSON.parse(fs.readFileSync(args.config_file, 'utf8'));
+}
+
+let persist;
+if (args.persist === 'mem') {
+    persist = new PersistMemInterface(config.persistMem);
+} else if (args.persist === 'file') {
+    persist = new PersistFileInterface(config.persistFile);
+} else if (args.persist === 'ring') {
+    persist = new PersistRingInterface(config.persistRing);
+} else {
+    console.error(`invalid persist ${args.persist}`);
+    process.exit(1);
+}
+
+let params = {
+    persist,
+    persistData: new PersistDataInterface(),
+};
+
+let oplogInterface;
+if (args.oplog_interface === 'bucketd') {
+    params = Object.assign(params, config.bucketdOplog);
+    oplogInterface = new BucketdOplogInterface(params);
+} else if (args.oplog_interface === 'mongo') {
+    params = Object.assign(params, config.mongoOplog);
+    oplogInterface = new MongoOplogInterface(params);
+} else {
+    console.error(`invalid oplog-interface ${args.oplog_interface}`);
+    process.exit(1);
+}
+
+if (args.start) {
+    if (args.bucket === undefined) {
+        console.error('please provide bucket');
+        process.exit(1);
+    }
+    oplogInterface.start(
+        {
+            filterName: args.bucket,
+            filterType: 'bucket',
+            bucket: {
+                bucketName: args.bucket,
+            },
+        },
+        err => {
+            if (err) {
+                console.error(err);
+                process.exit(1);
+            }
+            console.log('exiting...');
+            return;
+        });
+} else {
+    console.error('please provide an option');
+    process.exit(1);
+}
diff --git a/yarn.lock b/yarn.lock
index 3bb78c102..870595c5a 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1682,6 +1682,11 @@ async@^3.2.0:
   resolved "https://registry.yarnpkg.com/async/-/async-3.2.3.tgz#ac53dafd3f4720ee9e8a160628f18ea91df196c9"
   integrity sha512-spZRyzKL5l5BZQrr/6m/SqFdBN0q3OCI0f9rjfBzCMBIP4p75P620rR3gTmaksNOhmzgdxcaxdNfMy6anrbM0g==
 
+async@~0.2.7:
+  version "0.2.10"
+  resolved "https://registry.yarnpkg.com/async/-/async-0.2.10.tgz#b6bbe0b0674b9d719708ca38de8c237cb526c3d1"
+  integrity sha1-trvgsGdLnXGXCMo43owjfLUmw9E=
+
 async@~2.1.5:
   version "2.1.5"
   resolved "https://registry.yarnpkg.com/async/-/async-2.1.5.tgz#e587c68580994ac67fc56ff86d3ac56bdbe810bc"
@@ -4895,6 +4900,11 @@ memory-pager@^1.0.2:
   resolved "https://registry.yarnpkg.com/memory-pager/-/memory-pager-1.5.0.tgz#d8751655d22d384682741c972f2c3d6dfa3e66b5"
   integrity sha512-ZS4Bp4r/Zoeq6+NLJpP+0Zzm0pR8whtGPf1XExKLJBAczGMnSi3It14OiNCStjQjM6NU1okjQGSxgEZN8eBYKg==
 
+memorystream@^0.3.1:
+  version "0.3.1"
+  resolved "https://registry.yarnpkg.com/memorystream/-/memorystream-0.3.1.tgz#86d7090b30ce455d63fbae12dda51a47ddcaf9b2"
+  integrity sha1-htcJCzDORV1j+64S3aUaR93K+bI=
+
 merge-stream@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/merge-stream/-/merge-stream-2.0.0.tgz#52823629a14dd00c9770fb6ad47dc6310f2c1f60"
@@ -5203,6 +5213,14 @@ node-releases@^2.0.2:
   resolved "https://registry.yarnpkg.com/node-releases/-/node-releases-2.0.2.tgz#7139fe71e2f4f11b47d4d2986aaf8c48699e0c01"
   integrity sha512-XxYDdcQ6eKqp/YjI+tb2C5WM2LgjnZrfYg4vgQt49EK268b6gYCHsBLrK2qvJo4FmCtqmKezb0WZFK4fkrZNsg==
 
+node-zookeeper-client@^0.2.2:
+  version "0.2.3"
+  resolved "https://registry.yarnpkg.com/node-zookeeper-client/-/node-zookeeper-client-0.2.3.tgz#48c79129c56b8e898df9bd3bdad9e27dcad63851"
+  integrity sha512-V4gVHxzQ42iwhkANpPryzfjmqi3Ql3xeO9E/px7W5Yi774WplU3YtqUpnvcL/eJit4UqcfuLOgZLkpf0BPhHmg==
+  dependencies:
+    async "~0.2.7"
+    underscore "~1.4.4"
+
 nopt@^5.0.0:
   version "5.0.0"
   resolved "https://registry.yarnpkg.com/nopt/-/nopt-5.0.0.tgz#530942bb58a512fccafe53fe210f13a25355dc88"
@@ -5508,6 +5526,11 @@ pluralize@^1.2.1:
   resolved "https://registry.yarnpkg.com/pluralize/-/pluralize-1.2.1.tgz#d1a21483fd22bb41e58a12fa3421823140897c45"
   integrity sha1-0aIUg/0iu0HlihL6NCGCMUCJfEU=
 
+prando@^6.0.1:
+  version "6.0.1"
+  resolved "https://registry.yarnpkg.com/prando/-/prando-6.0.1.tgz#ffa8de84c2adc4975dd9df37ae4ada0458face53"
+  integrity sha512-ghUWxQ1T9IJmPu6eshc3VU0OwveUtXQ33ZLXYUcz1Oc5ppKLDXKp0TBDj6b0epwhEctzcQSNGR2iHyvQSn4W5A==
+
 prelude-ls@~1.1.2:
   version "1.1.2"
   resolved "https://registry.yarnpkg.com/prelude-ls/-/prelude-ls-1.1.2.tgz#21932a549f5e52ffd9a827f570e04be62a97da54"
@@ -6726,6 +6749,11 @@ unbzip2-stream@^1.0.9:
     buffer "^5.2.1"
     through "^2.3.8"
 
+underscore@~1.4.4:
+  version "1.4.4"
+  resolved "https://registry.yarnpkg.com/underscore/-/underscore-1.4.4.tgz#61a6a32010622afa07963bf325203cf12239d604"
+  integrity sha1-YaajIBBiKvoHljvzJSA88SI51gQ=
+
 underscore@~1.8.3:
   version "1.8.3"
   resolved "https://registry.yarnpkg.com/underscore/-/underscore-1.8.3.tgz#4f3fb53b106e6097fcf9cb4109f2a5e9bdfa5022"