MongoDB Replica,Shard Cluster 中央大學電算中心 楊素秋

OUTLINE 1. MongoDB Replica 2. Deploy a Replica Set 3. Sharing Cluster 4. Deploy a Sharded Cluster 5. Conclusion

1. MongoDB Replica Provides redundancy –protects a database from loss of a single server Increases data availability –recover from hardware failure service interruptions

2. Deploy a Replica Set 安裝 / 啟動 mongoDB on each hosts – 設定 /etc/mongod.conf service mongod restart 在 primary host ( ) –rs.initiate() –rs.add(“ :27017”) –rs.add(“ :27017”) –rs.addArb(“ :27017”)

Priority –cfg = rs.conf() –cfg.members[0].priority = 2.0 –cfg.members[1].priority = 0.5 –rs.reconfig(cfg) 2. Deploy a Replica Set (cont.)

Slave Node –MongoDBManager.java 2. Deploy a Replica Set (cont.) public static synchronized DB getDB() throws Exception { if(mongo == null) { mongo = new Mongo(); mongo.slaveOk(); } return mongo.getDB("fdns"); } public static synchronized Mongo getMongo() throws Exception { if(mongo == null) { mongo = new Mongo(); mongo.slaveOk(); } return mongo; }

Slave Node –mongo shell use fdns rs.slaveOk() show collections –mongo shell db.collectionName.remove() // FAIL db.collectionName.drop() 2. Deploy a Replica Set (cont.)

3. Sharing Cluster Single machine challenges –High query rates exhaust CPU capacity –Larger data sets exceed the storage capacity Referances – –

3. Sharing Cluster(cont.) Sharded Cluster Components –Shards holds a subset of a collection’s data a single mongod instance, or a replica setmongodreplica set –Config Servers a mongod instancemongod –holds metadata about the cluster –metadata maps chunks to shardschunks

3. Sharing Cluster (cont.) –Routing Instances a mongos instancemongos –routes the reads and writes from applications to the shards Applications do not access the shards directly

3. Sharing Cluster (cont.) Vertical scaling –adds more CPU and storage resources to increase capacity horizontal scaling (Sharding) divides the data set distributes data over multiple servers(shards) –Each shard is an independent database –shards make up a single logical database

Range based partitioning –MongoDB divides the data set into ranges determined by the shard key values to provide

Hash Based Sharding MongoDB computes a hash of a field’s value –uses these hashes to create chunks.

4. Deploy a Shard Cluster – y-shard-cluster/

5. Conclusion Replica Set ** –Primary : service –Secondary : Data Mining Apache Mahout: cluster, classification Mining flooding, attacks traffic –Arbiter Sharing Cluster –Load balance –Scalability