mongodb的sharding叢集由以下3個服務組成：

Shards Server: 每個shard由一個或多個mongod程式組成，用於儲存資料

Config Server: 用於儲存叢集的Metadata資訊，包括每個Shard的資訊和chunks資訊

Route Server: 用於提供路由服務，由Client連線，使整個Cluster看起來像單個DB伺服器

另外，Chunks是指MongoDB中一段連續的資料塊，預設大小是200M，一個Chunk位於其中一臺Shard伺服器上

下面，搭建一個Cluster，它由4臺伺服器組成，包括3個Shard，3個Config，1個Route

搭建mongodb sharding 配置過程

1 建立資料存放目錄

/opt/mongodata/r1

/opt/mongodata/r2

/opt/mongodata/r3

--注意配置順序

rac1

mkdir -p /opt/mongodata/config1

rac2

mkdir -p /opt/mongodata/config2

rac3

mkdir -p /opt/mongodata/config3

rac4

mkdir -p /opt/mongodata/mongos

2 配置config

rac1

[mongodb@rac1 bin]$ ./mongod --configsvr --dbpath=/opt/mongodata/config1 --port 28001 --logpath=/opt/mongodata/config1/config.log &

[1] 19996

[mongodb@rac1 bin]$ all output going to: /opt/mongodata/config1/config.log

rac2

[mongodb@rac2 bin]$ ./mongod --configsvr --dbpath=/opt/mongodata/config2 --port 28002 --logpath=/opt/mongodata/config2/config.log &

[1] 27223

[mongodb@rac2 bin]$ all output going to: /opt/mongodata/config2/config.log

rac3

[mongodb@rac3 bin]$ ./mongod --configsvr --dbpath=/opt/mongodata/config3 --port 28003 --logpath=/opt/mongodata/config3/config.log &

[1] 31020

[mongodb@rac3 bin]$ all output going to: /opt/mongodata/config3/config.log

3 配置路由設定

rac4

[mongodb@rac4 bin]$ ./mongos --chunkSize 1 --configdb "rac1:28001,rac2:28002,rac3:28003" --logpath /opt/mongodata/mongos/mongos.log &

NOTE:mongos 不需要-dbpath

4 配置sharding 節點

rac1

[mongodb@rac1 bin]$ ./mongod -shardsvr -dbpath=/opt/mongodata/r1 -port 27018 -logpath=/opt/mongodata/r1/27018.log &

rac2

[mongodb@rac2 bin]$ ./mongod -shardsvr -dbpath=/opt/mongodata/r2 -port 27019 -logpath=/opt/mongodata/r2/27019.log &

rac3

[mongodb@rac3 bin]$ ./mongod -shardsvr -dbpath=/opt/mongodata/r3 -port 27020 -logpath=/opt/mongodata/r3/27020.log &

5 在路由伺服器上進行新增shard配置：

addshard : 新增 Shard Server，相關的命令還有 listshards 和 removeshard。如果是要新增replica set 的shard 其語法是：db.runCommand({addshard:'replica set 的名字/IP:PORT,[IP:PORT,...]'});

enablesharding : 用於設定可以被分佈儲存的資料庫。

啟用指定資料庫的分片功能，這樣資料庫中的不同的collections會被分配到不同的shard上面，然而同一個collection會在同一個shard上面。

shardcollection : 用於設定具體被切塊的集合名稱，且必須指定 Shard Key，系統會自動建立索引。要進行collection級別的shard，必須執行

db.runCommand( { shardcollection : “”,key : });

namespace ：是collection的名字

shardkeypatternobject：片健，對一個集合進行分片時要設定一個欄位或者說鍵作為拆分的依據。

Note：

1 要進行collection級別的shard 必須先啟用資料庫級別的shard。

2 Sharded Collection 只能有一個 unique index，且必須是 shard key。

官方文件：a sharded collection can have only one unique index, which must exist on the shard key.NO other unique indexes can exist on the collection.

mongos> db.runCommand({addshard:'10.250.7.225:27018'});

{ "shardAdded" : "shard0000", "ok" : 1 }

mongos> db.runCommand({addshard:'10.250.7.249:27019'});

{ "shardAdded" : "shard0001", "ok" : 1 }

mongos> db.runCommand({addshard:'10.250.7.241:27020'});

{ "shardAdded" : "shard0002", "ok" : 1 }

當然如果是replica set + sharding 架構也可以使用db.runCommand({addshard:'replica set 的名字/IP:PORT,[IP:PORT,...]',name:"shard的名字",maxSize;N});

Name:用於指定每個shard的名字，不指定的話系統將自動分配
maxSize:指定各個shard可使用的最大磁碟空間，單位megabytes

mongos>

mongos> db.runCommand({"enablesharding": "test"})

{ "ok" : 1 }

mongos> db.runCommand({listshards:1});

{

"shards" : [

{

"_id" : "shard0000",

"host" : "10.250.7.225:27018"

},

{

"_id" : "shard0001",

"host" : "10.250.7.249:27019"

},

{

"_id" : "shard0002",

"host" : "10.250.7.241:27020"

}

],

"ok" : 1

}

mongos> printShardingStatus();

--- Sharding Status ---

sharding version: { "_id" : 1, "version" : 3 }

shards:

{ "_id" : "shard0000", "host" : "10.250.7.225:27018" }

{ "_id" : "shard0001", "host" : "10.250.7.249:27019" }

{ "_id" : "shard0002", "host" : "10.250.7.241:27020" }

databases:

{ "_id" : "admin", "partitioned" : false, "primary" : "config" }

{ "_id" : "test", "partitioned" : true, "primary" : "shard0000" }

mongos> db.runCommand({shardcollection:'test.yql',key:{_id:1}, unique : true});

{ "collectionsharded" : "test.yql", "ok" : 1 }

mongos> use test

switched to db test

mongos>

mongos> db.yql.insert({id:1,val:"this is a message on rac4 mongos !"});

mongos> db.yql.insert({id:2,val:"this is a message on rac4:27020 --2011-11-02 9:47!"});

mongos> db.yql.insert({id:2,val:"this is a message on rac4:27020 --2011-11-02 9:49!"});

mongos> db.yql.insert({id:3,val:"this is a message on rac4:27020 --2011-11-02 9:50!"});

mongos> db.yql.insert({id:4,val:"this is a message on rac4:27020 --2011-11-02 9:52!"});

mongos> db.yql.insert({id:5,val:"this is a message on rac4:27020 --2011-11-02 9:53!"});

mongos> db.yql.insert({id:6,val:"this is a message on rac4:27020 --2011-11-02 9:55!"});

mongos> db.yql.insert({id:7,val:"this is a message on rac4:27020 --2011-11-02 9:56!"});

mongos> db.yql.insert({id:8,val:"this is a message on rac4:27020 --2011-11-02 9:56!"});

mongos> db.yql.insert({id:9,val:"this is a message on rac4:27020 --2011-11-02 9:57!"});

mongos> db.yql.insert({id:10,val:"this is a message on rac4:27020 --2011-11-02 9:58!"});

mongos> db.yql.insert({id:11,val:"this is a message on rac4:27020 --2011-11-02 9:59!"});

mongos> db.yql.insert({id:12,val:"this is a message on rac4:27020 --2011-11-02 10:00!"});

mongos> db.yql.insert({id:13,val:"this is a message on rac4:27020 --2011-11-02 10:01!"});

mongos> db.yql.insert({id:14,val:"this is a message on rac4:27020 --2011-11-02 10:02!"});

mongos> db.yql.insert({id:15,val:"this is a message on rac4:27020 --2011-11-02 10:03!"});

mongos> db.yql.insert({id:16,val:"this is a message on rac4:27020 --2011-11-02 10:04!"});

mongos> db.yql.find();

{ "_id" : ObjectId("4eb298b3adbd9673afee95e3"), "id" : 1, "val" : "this is a message on rac4 mongos !" }

{ "_id" : ObjectId("4eb2995badbd9673afee95e4"), "id" : 2, "val" : "this is a message on rac4:27020 --2011-11-02 9:47!" }

{ "_id" : ObjectId("4eb29962adbd9673afee95e5"), "id" : 2, "val" : "this is a message on rac4:27020 --2011-11-02 9:49!" }

{ "_id" : ObjectId("4eb29970adbd9673afee95e6"), "id" : 3, "val" : "this is a message on rac4:27020 --2011-11-02 9:50!" }

{ "_id" : ObjectId("4eb2997badbd9673afee95e7"), "id" : 4, "val" : "this is a message on rac4:27020 --2011-11-02 9:52!" }

{ "_id" : ObjectId("4eb29985adbd9673afee95e8"), "id" : 5, "val" : "this is a message on rac4:27020 --2011-11-02 9:53!" }

{ "_id" : ObjectId("4eb299eaadbd9673afee95e9"), "id" : 6, "val" : "this is a message on rac4:27020 --2011-11-02 9:55!" }

{ "_id" : ObjectId("4eb299f3adbd9673afee95ea"), "id" : 7, "val" : "this is a message on rac4:27020 --2011-11-02 9:56!" }

{ "_id" : ObjectId("4eb29a59adbd9673afee95eb"), "id" : 8, "val" : "this is a message on rac4:27020 --2011-11-02 9:56!" }

{ "_id" : ObjectId("4eb29a59adbd9673afee95ec"), "id" : 9, "val" : "this is a message on rac4:27020 --2011-11-02 9:57!" }

{ "_id" : ObjectId("4eb29a59adbd9673afee95ed"), "id" : 10, "val" : "this is a message on rac4:27020 --2011-11-02 9:58!" }

{ "_id" : ObjectId("4eb29a59adbd9673afee95ee"), "id" : 11, "val" : "this is a message on rac4:27020 --2011-11-02 9:59!" }

{ "_id" : ObjectId("4eb29a59adbd9673afee95ef"), "id" : 12, "val" : "this is a message on rac4:27020 --2011-11-02 10:00!" }

{ "_id" : ObjectId("4eb29a59adbd9673afee95f0"), "id" : 13, "val" : "this is a message on rac4:27020 --2011-11-02 10:01!" }

{ "_id" : ObjectId("4eb29a59adbd9673afee95f1"), "id" : 14, "val" : "this is a message on rac4:27020 --2011-11-02 10:02!" }

{ "_id" : ObjectId("4eb29a59adbd9673afee95f2"), "id" : 15, "val" : "this is a message on rac4:27020 --2011-11-02 10:03!" }

{ "_id" : ObjectId("4eb29a59adbd9673afee95f3"), "id" : 16, "val" : "this is a message on rac4:27020 --2011-11-02 10:04!" }

用 db..stats() 可以檢視具體的 Shard 儲存資訊

mongos> db.yql.stats();

{

"sharded" : true,

"flags" : 1,

"ns" : "test.yql",

"count" : 17,

"numExtents" : 1,

"size" : 1616,

"storageSize" : 8192,

"totalIndexSize" : 8176,

"indexSizes" : {

"_id_" : 8176

},

"avgObjSize" : 95.05882352941177,

"nindexes" : 1,

"nchunks" : 1,

"shards" : {

"shard0000" : { --表示yql被拆分到了10.250.7.225這臺機器上了

"ns" : "test.yql",

"count" : 17,

"size" : 1616,

"avgObjSize" : 95.05882352941177,

"storageSize" : 8192,

"numExtents" : 1,

"nindexes" : 1,

"lastExtentSize" : 8192,

"paddingFactor" : 1,

"flags" : 1,

"totalIndexSize" : 8176,

"indexSizes" : {

"_id_" : 8176

},

"ok" : 1

}

},

"ok" : 1

}

mongos>

【Mongodb】Sharding 叢集配置

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