MongoDB之分片
1、環境
作業系統資訊：
伺服器規劃：
從上表可以看到有四個元件：mongos、config server、shard、replica set。
mongos：資料庫叢集請求的入口，所有的請求都透過mongos進行協調，不需要在應用程式新增一個路由選擇器，mongos自己就是一個請求分發中心，它負責把對應的資料請求轉發到對應的shard伺服器上。在生產環境通常有多mongos作為請求的入口，防止其中一個掛掉所有的mongodb請求都沒有辦法操作。
config server：顧名思義為配置伺服器，儲存所有資料庫元資訊（路由、分片）的配置。mongos本身沒有物理儲存分片伺服器和資料路由資訊，只是快取在記憶體裡，配置伺服器則實際儲存這些資料。mongos第一次啟動或者關掉重啟就會從 config server 載入配置資訊，以後如果配置伺服器資訊變化會通知到所有的 mongos 更新自己的狀態，這樣 mongos 就能繼續準確路由。在生產環境通常有多個 config server 配置伺服器（必須配置為１個或者３個），因為它儲存了分片路由的後設資料，防止資料丟失！
shard：分片（sharding）是指將資料庫拆分，將其分散在不同的機器上的過程。將資料分散到不同的機器上，不需要功能強大的伺服器就可以儲存更多的資料和處理更大的負載。基本思想就是將集合切成小塊，這些塊分散到若干片裡，每個片只負責總資料的一部分，最後透過一個均衡器來對各個分片進行均衡（資料遷移）。
replica set：中文翻譯副本集，其實就是shard的備份，防止shard掛掉之後資料丟失。複製提供了資料的冗餘備份，並在多個伺服器上儲存資料副本，提高了資料的可用性， 並可以保證資料的安全性。
仲裁者（Arbiter）：是複製集中的一個MongoDB例項，它並不儲存資料。仲裁節點使用最小的資源，不能將Arbiter部署在同一個資料集節點中，可以部署在其他應用伺服器或者監視伺服器中，也可部署在單獨的虛擬機器中。為了確保複製集中有奇數的投票成員（包括primary），需要新增仲裁節點做為投票，否則primary不能執行時不會自動切換primary。
簡單瞭解之後，可以這樣總結一下，應用請求mongos來操作mongodb的增刪改查，配置伺服器儲存資料庫元資訊，並且和mongos做同步，資料最終存入在shard（分片）上，為了防止資料丟失同步在副本集中儲存了一份，仲裁在資料儲存到分片的時候決定儲存到哪個節點。
總共規劃了mongos 3個， config server 3個，資料分3片 shard server 3個，每個shard 有一個副本一個仲裁也就是 3 * 2 = 6 個，總共需要部署15個例項。這些例項可以部署在獨立機器也可以部署在一臺機器，我們這裡測試資源有限，只准備了 3臺機器，在同一臺機器只要埠不同就可以了。
2、安裝mongodb
分別在3臺機器上面安裝mongodb
[root@D2-POMS15 ~]# tar -xvzf mongodb-linux-x86_64-rhel62-3.4.7.tgz -C /usr/local/
[root@D2-POMS15 ~]# mv /usr/local/mongodb-linux-x86_64-rhel62-3.4.7/ /usr/local/mongodb
配置環境變數
[root@D2-POMS15 ~]# vim .bash_profile
export PATH=$PATH:/usr/local/mongodb/bin/
[root@D2-POMS15 ~]# source .bash_profile
分別在每臺機器建立conf、mongos、config、shard1、shard2、shard3六個目錄，因為mongos不儲存資料，只需要建立日誌檔案目錄即可。
[root@D2-POMS15 ~]# mkdir -p /usr/local/mongodb/conf
[root@D2-POMS15 ~]# mkdir -p /usr/local/mongodb/mongos/log
[root@D2-POMS15 ~]# mkdir -p /usr/local/mongodb/config/data
[root@D2-POMS15 ~]# mkdir -p /usr/local/mongodb/config/log
[root@D2-POMS15 ~]# mkdir -p /usr/local/mongodb/shard1/data
[root@D2-POMS15 ~]# mkdir -p /usr/local/mongodb/shard1/log
[root@D2-POMS15 ~]# mkdir -p /usr/local/mongodb/shard2/data
[root@D2-POMS15 ~]# mkdir -p /usr/local/mongodb/shard2/log
[root@D2-POMS15 ~]# mkdir -p /usr/local/mongodb/shard3/data
[root@D2-POMS15 ~]# mkdir -p /usr/local/mongodb/shard3/log
3、config server配置伺服器
mongodb3.4以後要求配置伺服器也建立副本集，不然叢集搭建不成功。
在三臺伺服器上面新增配置檔案：
[root@D2-POMS15 ~]# vi /usr/local/mongodb/conf/config.conf
## 配置檔案內容
pidfilepath = /usr/local/mongodb/config/log/configsrv.pid
dbpath = /usr/local/mongodb/config/data
logpath = /usr/local/mongodb/config/log/congigsrv.log
logappend = true
bind_ip = 0.0.0.0
port = 21000
fork = true
#declare this is a config db of a cluster;
configsvr = true
#副本集名稱
replSet=configs
#設定最大連線數
maxConns=20000
分別啟動三臺伺服器的config server
[root@D2-POMS15 ~]# mongod -f /usr/local/mongodb/conf/config.conf
about to fork child process, waiting until server is ready for connections.
forked process: 15368
child process started successfully, parent exiting
登入任意一臺配置伺服器，初始化配置副本集
[root@D2-POMS15 ~]# mongo --port 21000
> config = {
... _id : "configs",
... members : [
... {_id : 0, host : "10.163.97.15:21000" },
... {_id : 1, host : "10.163.97.16:21000" },
... {_id : 2, host : "10.163.97.17:21000" }
... ]
... }
{
"_id" : "configs",
"members" : [
{
"_id" : 0,
"host" : "10.163.97.15:21000"
},
{
"_id" : 1,
"host" : "10.163.97.16:21000"
},
{
"_id" : 2,
"host" : "10.163.97.17:21000"
}
]
}
> rs.initiate(config)
{ "ok" : 1 }
其中，"_id" : "configs"應與配置檔案中配置的replSet一致，"members" 中的 "host" 為三個節點的 ip 和 port。
4、配置分片副本集(三臺機器)
設定第一個分片副本集
新增配置檔案：
[root@D2-POMS15 ~]# vi /usr/local/mongodb/conf/shard1.conf
#配置檔案內容
pidfilepath = /usr/local/mongodb/shard1/log/shard1.pid
dbpath = /usr/local/mongodb/shard1/data
logpath = /usr/local/mongodb/shard1/log/shard1.log
logappend = true
bind_ip = 0.0.0.0
port = 27001
fork = true
#開啟web監控
httpinterface=true
rest=true
#副本集名稱
replSet=shard1
#declare this is a shard db of a cluster;
shardsvr = true
#設定最大連線數
maxConns=20000
啟動三臺伺服器的shard1 server
[root@D2-POMS15 ~]# mongod -f /usr/local/mongodb/conf/shard1.conf
about to fork child process, waiting until server is ready for connections.
forked process: 15497
child process started successfully, parent exiting
登陸一臺伺服器（不要在仲裁節點），初始化副本集
[root@D2-POMS15 ~]# mongo --port 27001
#使用admin資料庫
> use admin
switched to db admin
#定義副本集配置，第三個節點的 "arbiterOnly":true 代表其為仲裁節點。
> config = {
... _id : "shard1",
... members : [
... {_id : 0, host : "10.163.97.15:27001" },
... {_id : 1, host : "10.163.97.16:27001" },
... {_id : 2, host : "10.163.97.17:27001" , arbiterOnly: true }
... ]
... }
{
"_id" : "shard1",
"members" : [
{
"_id" : 0,
"host" : "10.163.97.15:27001"
},
{
"_id" : 1,
"host" : "10.163.97.16:27001"
},
{
"_id" : 2,
"host" : "10.163.97.17:27001",
"arbiterOnly" : true
}
]
}
#初始化副本集配置
> rs.initiate(config);
{ "ok" : 1 }
設定第二個分片副本集
新增配置檔案：
[root@D2-POMS15 ~]# vi /usr/local/mongodb/conf/shard2.conf
#配置檔案內容
pidfilepath = /usr/local/mongodb/shard2/log/shard2.pid
dbpath = /usr/local/mongodb/shard2/data
logpath = /usr/local/mongodb/shard2/log/shard2.log
logappend = true
bind_ip = 0.0.0.0
port = 27002
fork = true
#開啟web監控
httpinterface=true
rest=true
#副本集名稱
replSet=shard2
#declare this is a shard db of a cluster;
shardsvr = true
#設定最大連線數
maxConns=20000
啟動三臺伺服器的shard2 server：
[root@D2-POMS15 ~]# mongod -f /usr/local/mongodb/conf/shard2.conf
about to fork child process, waiting until server is ready for connections.
forked process: 15622
child process started successfully, parent exiting
登陸一臺伺服器（不要在仲裁節點），初始化副本集
[root@D2-POMS15 ~]# mongo --port 27002
> use admin
switched to db admin
> config = {
... _id : "shard2",
... members : [
... {_id : 0, host : "10.163.97.15:27002" , arbiterOnly: true },
... {_id : 1, host : "10.163.97.16:27002" },
... {_id : 2, host : "10.163.97.17:27002" }
... ]
... }
{
"_id" : "shard2",
"members" : [
{
"_id" : 0,
"host" : "10.163.97.15:27002",
"arbiterOnly" : true
},
{
"_id" : 1,
"host" : "10.163.97.16:27002"
},
{
"_id" : 2,
"host" : "10.163.97.17:27002"
}
]
}
> rs.initiate(config);
{ "ok" : 1 }
設定第三個分片副本集
新增配置檔案：
[root@D2-POMS15 ~]# vi /usr/local/mongodb/conf/shard3.conf
#配置檔案內容
pidfilepath = /usr/local/mongodb/shard3/log/shard3.pid
dbpath = /usr/local/mongodb/shard3/data
logpath = /usr/local/mongodb/shard3/log/shard3.log
logappend = true
bind_ip = 0.0.0.0
port = 27003
fork = true
#開啟web監控
httpinterface=true
rest=true
#副本集名稱
replSet=shard3
#declare this is a shard db of a cluster;
shardsvr = true
#設定最大連線數
maxConns=20000
啟動三臺伺服器的shard3 server
[root@D2-POMS15 ~]# mongod -f /usr/local/mongodb/conf/shard3.conf
about to fork child process, waiting until server is ready for connections.
forked process: 15742
child process started successfully, parent exiting
登陸一臺伺服器（不要在仲裁節點），初始化副本集
> use admin
switched to db admin
> config = {
... _id : "shard3",
... members : [
... {_id : 0, host : "10.163.97.15:27003" },
... {_id : 1, host : "10.163.97.16:27003" , arbiterOnly: true},
... {_id : 2, host : "10.163.97.17:27003" }
... ]
... }
{
"_id" : "shard3",
"members" : [
{
"_id" : 0,
"host" : "10.163.97.15:27003"
},
{
"_id" : 1,
"host" : "10.163.97.16:27003",
"arbiterOnly" : true
},
{
"_id" : 2,
"host" : "10.163.97.17:27003"
}
]
}
> rs.initiate(config);
{ "ok" : 1 }
可以看到目前已經啟動了配置伺服器和分片伺服器。
[root@D2-POMS15 ~]# ps -ef | grep mongo | grep -v grep
root 15368 1 0 15:52 ? 00:00:07 mongod -f /usr/local/mongodb/conf/config.conf
root 15497 1 0 16:00 ? 00:00:04 mongod -f /usr/local/mongodb/conf/shard1.conf
root 15622 1 0 16:06 ? 00:00:02 mongod -f /usr/local/mongodb/conf/shard2.conf
root 15742 1 0 16:21 ? 00:00:00 mongod -f /usr/local/mongodb/conf/shard3.conf
5、配置路由伺服器 mongos
在三臺伺服器上面新增配置檔案：
[root@D2-POMS15 ~]# vi /usr/local/mongodb/conf/mongos.conf
#內容
pidfilepath = /usr/local/mongodb/mongos/log/mongos.pid
logpath = /usr/local/mongodb/mongos/log/mongos.log
logappend = true
bind_ip = 0.0.0.0
port = 20000
fork = true
#監聽的配置伺服器,只能有1個或者3個 configs為配置伺服器的副本集名字
configdb = configs/10.163.97.15:21000,10.163.97.16:21000,10.163.97.17:21000
#設定最大連線數
maxConns=20000
啟動三臺伺服器的mongos server
[root@D2-POMS15 ~]# mongos -f /usr/local/mongodb/conf/mongos.conf
about to fork child process, waiting until server is ready for connections.
forked process: 20563
child process started successfully, parent exiting
[root@D2-POMS15 ~]# mongo --port 20000
mongos> db.stats()
{
"raw" : {
"shard1/10.163.97.15:27001,10.163.97.16:27001" : {
"db" : "admin",
"collections" : 1,
"views" : 0,
"objects" : 3,
"avgObjSize" : 146.66666666666666,
"dataSize" : 440,
"storageSize" : 36864,
"numExtents" : 0,
"indexes" : 2,
"indexSize" : 65536,
"ok" : 1,
"$gleStats" : {
"lastOpTime" : Timestamp(0, 0),
"electionId" : ObjectId("7fffffff0000000000000001")
}
},
"shard2/10.163.97.16:27002,10.163.97.17:27002" : {
"db" : "admin",
"collections" : 1,
"views" : 0,
"objects" : 2,
"avgObjSize" : 114,
"dataSize" : 228,
"storageSize" : 16384,
"numExtents" : 0,
"indexes" : 2,
"indexSize" : 32768,
"ok" : 1,
"$gleStats" : {
"lastOpTime" : Timestamp(0, 0),
"electionId" : ObjectId("7fffffff0000000000000001")
}
},
"shard3/10.163.97.15:27003,10.163.97.17:27003" : {
"db" : "admin",
"collections" : 1,
"views" : 0,
"objects" : 2,
"avgObjSize" : 114,
"dataSize" : 228,
"storageSize" : 16384,
"numExtents" : 0,
"indexes" : 2,
"indexSize" : 32768,
"ok" : 1,
"$gleStats" : {
"lastOpTime" : Timestamp(0, 0),
"electionId" : ObjectId("7fffffff0000000000000002")
}
}
},
"objects" : 7,
"avgObjSize" : 127.71428571428571,
"dataSize" : 896,
"storageSize" : 69632,
"numExtents" : 0,
"indexes" : 6,
"indexSize" : 131072,
"fileSize" : 0,
"extentFreeList" : {
"num" : 0,
"totalSize" : 0
},
"ok" : 1
}
6、啟用分片
目前搭建了mongodb配置伺服器、路由伺服器，各個分片伺服器，不過應用程式連線到mongos路由伺服器並不能使用分片機制，還需要在路由伺服器裡設定分片配置，讓分片生效。
登陸任意一臺mongos
[root@D2-POMS15 ~]# mongo --port 20000
#使用admin資料庫
mongos> use admin
switched to db admin
#串聯路由伺服器與分配副本集
mongos> sh.addShard("shard1/10.163.97.15:27001,10.163.97.16:27001,10.163.97.17:27001")
{ "shardAdded" : "shard1", "ok" : 1 }
mongos> sh.addShard("shard2/10.163.97.15:27002,10.163.97.16:27002,10.163.97.17:27002")
{ "shardAdded" : "shard2", "ok" : 1 }
mongos> sh.addShard("shard3/10.163.97.15:27003,10.163.97.16:27003,10.163.97.17:27003")
{ "shardAdded" : "shard3", "ok" : 1 }
#檢視叢集狀態
mongos> sh.status()
--- Sharding Status ---
sharding version: {
"_id" : 1,
"minCompatibleVersion" : 5,
"currentVersion" : 6,
"clusterId" : ObjectId("599d34bf612249caec3fc9fe")
}
shards:
{ "_id" : "shard1", "host" : "shard1/10.163.97.15:27001,10.163.97.16:27001", "state" : 1 }
{ "_id" : "shard2", "host" : "shard2/10.163.97.16:27002,10.163.97.17:27002", "state" : 1 }
{ "_id" : "shard3", "host" : "shard3/10.163.97.15:27003,10.163.97.17:27003", "state" : 1 }
active mongoses:
"3.4.7" : 1
autosplit:
Currently enabled: yes
balancer:
Currently enabled: yes
Currently running: no
Balancer lock taken at Wed Aug 23 2017 15:54:40 GMT+0800 (CST) by ConfigServer:Balancer
Failed balancer rounds in last 5 attempts: 0
Migration Results for the last 24 hours:
No recent migrations
databases:
7、測試
目前配置服務、路由服務、分片服務、副本集服務都已經串聯起來了，但我們的目的是希望插入資料，資料能夠自動分片。連線在mongos上，準備讓指定的資料庫、指定的集合分片生效。
[root@D2-POMS15 ~]# mongo --port 20000
mongos> use admin
switched to db admin
#指定testdb分片生效
mongos> db.runCommand({enablesharding :"testdb"});
{ "ok" : 1 }
#指定資料庫裡需要分片的集合和片鍵
mongos> db.runCommand( { shardcollection : "testdb.table1",key : {id: 1} } )
{ "collectionsharded" : "testdb.table1", "ok" : 1 }
mongos> sh.status()
--- Sharding Status ---
sharding version: {
"_id" : 1,
"minCompatibleVersion" : 5,
"currentVersion" : 6,
"clusterId" : ObjectId("599d34bf612249caec3fc9fe")
}
shards:
{ "_id" : "shard1", "host" : "shard1/10.163.97.15:27001,10.163.97.16:27001", "state" : 1 }
{ "_id" : "shard2", "host" : "shard2/10.163.97.16:27002,10.163.97.17:27002", "state" : 1 }
{ "_id" : "shard3", "host" : "shard3/10.163.97.15:27003,10.163.97.17:27003", "state" : 1 }
active mongoses:
"3.4.7" : 1
autosplit:
Currently enabled: yes
balancer:
Currently enabled: yes
Currently running: no
Balancer lock taken at Wed Aug 23 2017 15:54:40 GMT+0800 (CST) by ConfigServer:Balancer
Failed balancer rounds in last 5 attempts: 0
Migration Results for the last 24 hours:
4 : Success
databases:
{ "_id" : "testdb", "primary" : "shard1", "partitioned" : true }
testdb.table1
shard key: { "id" : 1 }
unique: false
balancing: true
chunks:
shard1 1
{ "id" : { "$minKey" : 1 } } -->> { "id" : { "$maxKey" : 1 } } on : shard1 Timestamp(1, 0)
以上就是設定testdb的 table1 表需要分片，根據 id 自動分片到 shard1 ，shard2，shard3 上面去。要這樣設定是因為不是所有mongodb 的資料庫和表 都需要分片！
測試分片：
#連線mongos伺服器
[root@D2-POMS15 ~]# mongo --port 20000
#使用testdb
mongos> use testdb
switched to db testdb
#插入測試資料
mongos> for(var i=1;i<=100000;i++){db.table1.insert({id:i,"test1":"testval1"})}
WriteResult({ "nInserted" : 1 })
#檢視分片情況
mongos> sh.status()
--- Sharding Status ---
sharding version: {
"_id" : 1,
"minCompatibleVersion" : 5,
"currentVersion" : 6,
"clusterId" : ObjectId("599d34bf612249caec3fc9fe")
}
shards:
{ "_id" : "shard1", "host" : "shard1/10.163.97.15:27001,10.163.97.16:27001", "state" : 1 }
{ "_id" : "shard2", "host" : "shard2/10.163.97.16:27002,10.163.97.17:27002", "state" : 1 }
{ "_id" : "shard3", "host" : "shard3/10.163.97.15:27003,10.163.97.17:27003", "state" : 1 }
active mongoses:
"3.4.7" : 1
autosplit:
Currently enabled: yes
balancer:
Currently enabled: yes
Currently running: no
Balancer lock taken at Wed Aug 23 2017 15:54:40 GMT+0800 (CST) by ConfigServer:Balancer
Failed balancer rounds in last 5 attempts: 0
Migration Results for the last 24 hours:
6 : Success
databases:
{ "_id" : "testdb", "primary" : "shard1", "partitioned" : true }
testdb.table1
shard key: { "id" : 1 }
unique: false
balancing: true
chunks:
shard1 1
shard2 1
shard3 1
{ "id" : { "$minKey" : 1 } } -->> { "id" : 2 } on : shard2 Timestamp(2, 0)
{ "id" : 2 } -->> { "id" : 20 } on : shard3 Timestamp(3, 0)
{ "id" : 20 } -->> { "id" : { "$maxKey" : 1 } } on : shard1 Timestamp(3, 1)
可以看到這裡分片很不均衡，原因是預設的chunkSize為64M，這裡的資料量沒有達到64M，可以修改一下chunkSize的大小，方便測試：
[root@D2-POMS15 ~]# mongo --port 20000
mongos> use config
switched to db config
mongos> db.settings.save( { _id:"chunksize", value: 1 } )
WriteResult({ "nMatched" : 0, "nUpserted" : 1, "nModified" : 0, "_id" : "chunksize" })
mongos> db.settings.find();
{ "_id" : "balancer", "stopped" : false, "mode" : "full" }
{ "_id" : "chunksize", "value" : 1 }
修改後重新來測試：
mongos> use testdb
switched to db testdb
mongos> db.table1.drop();
true
mongos> use admin
switched to db admin
mongos> db.runCommand( { shardcollection : "testdb.table1",key : {id: 1} } )
{ "collectionsharded" : "testdb.table1", "ok" : 1 }
mongos> use testdb
switched to db testdb
mongos> for(var i=1;i<=100000;i++){db.table1.insert({id:i,"test1":"testval1"})}
WriteResult({ "nInserted" : 1 })
mongos> sh.status()
--- Sharding Status ---
sharding version: {
"_id" : 1,
"minCompatibleVersion" : 5,
"currentVersion" : 6,
"clusterId" : ObjectId("599d34bf612249caec3fc9fe")
}
shards:
{ "_id" : "shard1", "host" : "shard1/10.163.97.15:27001,10.163.97.16:27001", "state" : 1 }
{ "_id" : "shard2", "host" : "shard2/10.163.97.16:27002,10.163.97.17:27002", "state" : 1 }
{ "_id" : "shard3", "host" : "shard3/10.163.97.15:27003,10.163.97.17:27003", "state" : 1 }
active mongoses:
"3.4.7" : 1
autosplit:
Currently enabled: yes
balancer:
Currently enabled: yes
Currently running: no
Balancer lock taken at Wed Aug 23 2017 15:54:40 GMT+0800 (CST) by ConfigServer:Balancer
Failed balancer rounds in last 5 attempts: 0
Migration Results for the last 24 hours:
14 : Success
databases:
{ "_id" : "testdb", "primary" : "shard1", "partitioned" : true }
testdb.table1
shard key: { "id" : 1 }
unique: false
balancing: true
chunks:
shard1 4
shard2 4
shard3 3
{ "id" : { "$minKey" : 1 } } -->> { "id" : 2 } on : shard2 Timestamp(5, 1)
{ "id" : 2 } -->> { "id" : 20 } on : shard3 Timestamp(6, 1)
{ "id" : 20 } -->> { "id" : 9729 } on : shard1 Timestamp(7, 1)
{ "id" : 9729 } -->> { "id" : 21643 } on : shard1 Timestamp(3, 3)
{ "id" : 21643 } -->> { "id" : 31352 } on : shard2 Timestamp(4, 2)
{ "id" : 31352 } -->> { "id" : 43021 } on : shard2 Timestamp(4, 3)
{ "id" : 43021 } -->> { "id" : 52730 } on : shard3 Timestamp(5, 2)
{ "id" : 52730 } -->> { "id" : 64695 } on : shard3 Timestamp(5, 3)
{ "id" : 64695 } -->> { "id" : 74404 } on : shard1 Timestamp(6, 2)
{ "id" : 74404 } -->> { "id" : 87088 } on : shard1 Timestamp(6, 3)
{ "id" : 87088 } -->> { "id" : { "$maxKey" : 1 } } on : shard2 Timestamp(7, 0)
mongos> db.table1.stats()
{
"sharded" : true,
"capped" : false,
"ns" : "testdb.table1",
"count" : 100000,
"size" : 5400000,
"storageSize" : 1736704,
"totalIndexSize" : 2191360,
"indexSizes" : {
"_id_" : 946176,
"id_1" : 1245184
},
"avgObjSize" : 54,
"nindexes" : 2,
"nchunks" : 11,
"shards" : {
"shard1" : {
"ns" : "testdb.table1",
"size" : 2376864,
"count" : 44016,
"avgObjSize" : 54,
"storageSize" : 753664,
"capped" : false,
"nindexes" : 2,
"totalIndexSize" : 933888,
"indexSizes" : {
"_id_" : 405504,
"id_1" : 528384
},
"ok" : 1
},
"shard2" : {
"ns" : "testdb.table1",
"size" : 1851768,
"count" : 34292,
"avgObjSize" : 54,
"storageSize" : 606208,
"capped" : false,
"nindexes" : 2,
"totalIndexSize" : 774144,
"indexSizes" : {
"_id_" : 335872,
"id_1" : 438272
},
"ok" : 1
},
"shard3" : {
"ns" : "testdb.table1",
"size" : 1171368,
"count" : 21692,
"avgObjSize" : 54,
"storageSize" : 376832,
"capped" : false,
"nindexes" : 2,
"totalIndexSize" : 483328,
"indexSizes" : {
"_id_" : 204800,
"id_1" : 278528
},
"ok" : 1
}
},
"ok" : 1
}
可以看到現在的資料分佈就均勻多了。
８、後期運維
啟動關閉
mongodb的啟動順序是，先啟動配置伺服器，在啟動分片，最後啟動mongos.
mongod -f /usr/local/mongodb/conf/config.conf
mongod -f /usr/local/mongodb/conf/shard1.conf
mongod -f /usr/local/mongodb/conf/shard2.conf
mongod -f /usr/local/mongodb/conf/shard3.conf
mongod -f /usr/local/mongodb/conf/mongos.conf
關閉時，直接killall殺掉所有程式
killall mongod
killall mongos
參考：
http://www.cnblogs.com/ityouknow/p/7344005.html
作業系統資訊：
| IP | 作業系統 | MongoDB |
| 10.163.91.15 | RHLE6.5_x64 | mongodb-linux-x86_64-rhel62-3.4.7.tgz |
| 10.163.91.16 | RHLE6.5_x64 | mongodb-linux-x86_64-rhel62-3.4.7.tgz |
| 10.163.91.17 | RHLE6.5_x64 | mongodb-linux-x86_64-rhel62-3.4.7.tgz |
伺服器規劃：
| 10.163.97.15 | 10.163.97.16 | 10.163.97.17 | 埠 |
| mongos | mongos | mongos | 20000 |
| config server | config server | config server | 21000 |
| shard server1 主節點 | shard server1 副節點 | shard server1 仲裁 | 27001 |
| shard server2 仲裁 | shard server2 主節點 | shard server2 副節點 | 27002 |
| shard server3 副節點 | shard server3 仲裁 | shard server3 主節點 | 27003 |
從上表可以看到有四個元件：mongos、config server、shard、replica set。
mongos：資料庫叢集請求的入口，所有的請求都透過mongos進行協調，不需要在應用程式新增一個路由選擇器，mongos自己就是一個請求分發中心，它負責把對應的資料請求轉發到對應的shard伺服器上。在生產環境通常有多mongos作為請求的入口，防止其中一個掛掉所有的mongodb請求都沒有辦法操作。
config server：顧名思義為配置伺服器，儲存所有資料庫元資訊（路由、分片）的配置。mongos本身沒有物理儲存分片伺服器和資料路由資訊，只是快取在記憶體裡，配置伺服器則實際儲存這些資料。mongos第一次啟動或者關掉重啟就會從 config server 載入配置資訊，以後如果配置伺服器資訊變化會通知到所有的 mongos 更新自己的狀態，這樣 mongos 就能繼續準確路由。在生產環境通常有多個 config server 配置伺服器（必須配置為１個或者３個），因為它儲存了分片路由的後設資料，防止資料丟失！
shard：分片（sharding）是指將資料庫拆分，將其分散在不同的機器上的過程。將資料分散到不同的機器上，不需要功能強大的伺服器就可以儲存更多的資料和處理更大的負載。基本思想就是將集合切成小塊，這些塊分散到若干片裡，每個片只負責總資料的一部分，最後透過一個均衡器來對各個分片進行均衡（資料遷移）。
replica set：中文翻譯副本集，其實就是shard的備份，防止shard掛掉之後資料丟失。複製提供了資料的冗餘備份，並在多個伺服器上儲存資料副本，提高了資料的可用性， 並可以保證資料的安全性。
仲裁者（Arbiter）：是複製集中的一個MongoDB例項，它並不儲存資料。仲裁節點使用最小的資源，不能將Arbiter部署在同一個資料集節點中，可以部署在其他應用伺服器或者監視伺服器中，也可部署在單獨的虛擬機器中。為了確保複製集中有奇數的投票成員（包括primary），需要新增仲裁節點做為投票，否則primary不能執行時不會自動切換primary。
簡單瞭解之後，可以這樣總結一下，應用請求mongos來操作mongodb的增刪改查，配置伺服器儲存資料庫元資訊，並且和mongos做同步，資料最終存入在shard（分片）上，為了防止資料丟失同步在副本集中儲存了一份，仲裁在資料儲存到分片的時候決定儲存到哪個節點。
總共規劃了mongos 3個， config server 3個，資料分3片 shard server 3個，每個shard 有一個副本一個仲裁也就是 3 * 2 = 6 個，總共需要部署15個例項。這些例項可以部署在獨立機器也可以部署在一臺機器，我們這裡測試資源有限，只准備了 3臺機器，在同一臺機器只要埠不同就可以了。
2、安裝mongodb
分別在3臺機器上面安裝mongodb
[root@D2-POMS15 ~]# tar -xvzf mongodb-linux-x86_64-rhel62-3.4.7.tgz -C /usr/local/
[root@D2-POMS15 ~]# mv /usr/local/mongodb-linux-x86_64-rhel62-3.4.7/ /usr/local/mongodb
配置環境變數
[root@D2-POMS15 ~]# vim .bash_profile
export PATH=$PATH:/usr/local/mongodb/bin/
[root@D2-POMS15 ~]# source .bash_profile
分別在每臺機器建立conf、mongos、config、shard1、shard2、shard3六個目錄，因為mongos不儲存資料，只需要建立日誌檔案目錄即可。
[root@D2-POMS15 ~]# mkdir -p /usr/local/mongodb/conf
[root@D2-POMS15 ~]# mkdir -p /usr/local/mongodb/mongos/log
[root@D2-POMS15 ~]# mkdir -p /usr/local/mongodb/config/data
[root@D2-POMS15 ~]# mkdir -p /usr/local/mongodb/config/log
[root@D2-POMS15 ~]# mkdir -p /usr/local/mongodb/shard1/data
[root@D2-POMS15 ~]# mkdir -p /usr/local/mongodb/shard1/log
[root@D2-POMS15 ~]# mkdir -p /usr/local/mongodb/shard2/data
[root@D2-POMS15 ~]# mkdir -p /usr/local/mongodb/shard2/log
[root@D2-POMS15 ~]# mkdir -p /usr/local/mongodb/shard3/data
[root@D2-POMS15 ~]# mkdir -p /usr/local/mongodb/shard3/log
3、config server配置伺服器
mongodb3.4以後要求配置伺服器也建立副本集，不然叢集搭建不成功。
在三臺伺服器上面新增配置檔案：
[root@D2-POMS15 ~]# vi /usr/local/mongodb/conf/config.conf
## 配置檔案內容
pidfilepath = /usr/local/mongodb/config/log/configsrv.pid
dbpath = /usr/local/mongodb/config/data
logpath = /usr/local/mongodb/config/log/congigsrv.log
logappend = true
bind_ip = 0.0.0.0
port = 21000
fork = true
#declare this is a config db of a cluster;
configsvr = true
#副本集名稱
replSet=configs
#設定最大連線數
maxConns=20000
分別啟動三臺伺服器的config server
[root@D2-POMS15 ~]# mongod -f /usr/local/mongodb/conf/config.conf
about to fork child process, waiting until server is ready for connections.
forked process: 15368
child process started successfully, parent exiting
登入任意一臺配置伺服器，初始化配置副本集
[root@D2-POMS15 ~]# mongo --port 21000
> config = {
... _id : "configs",
... members : [
... {_id : 0, host : "10.163.97.15:21000" },
... {_id : 1, host : "10.163.97.16:21000" },
... {_id : 2, host : "10.163.97.17:21000" }
... ]
... }
{
"_id" : "configs",
"members" : [
{
"_id" : 0,
"host" : "10.163.97.15:21000"
},
{
"_id" : 1,
"host" : "10.163.97.16:21000"
},
{
"_id" : 2,
"host" : "10.163.97.17:21000"
}
]
}
> rs.initiate(config)
{ "ok" : 1 }
其中，"_id" : "configs"應與配置檔案中配置的replSet一致，"members" 中的 "host" 為三個節點的 ip 和 port。
4、配置分片副本集(三臺機器)
設定第一個分片副本集
新增配置檔案：
[root@D2-POMS15 ~]# vi /usr/local/mongodb/conf/shard1.conf
#配置檔案內容
pidfilepath = /usr/local/mongodb/shard1/log/shard1.pid
dbpath = /usr/local/mongodb/shard1/data
logpath = /usr/local/mongodb/shard1/log/shard1.log
logappend = true
bind_ip = 0.0.0.0
port = 27001
fork = true
#開啟web監控
httpinterface=true
rest=true
#副本集名稱
replSet=shard1
#declare this is a shard db of a cluster;
shardsvr = true
#設定最大連線數
maxConns=20000
啟動三臺伺服器的shard1 server
[root@D2-POMS15 ~]# mongod -f /usr/local/mongodb/conf/shard1.conf
about to fork child process, waiting until server is ready for connections.
forked process: 15497
child process started successfully, parent exiting
登陸一臺伺服器（不要在仲裁節點），初始化副本集
[root@D2-POMS15 ~]# mongo --port 27001
#使用admin資料庫
> use admin
switched to db admin
#定義副本集配置，第三個節點的 "arbiterOnly":true 代表其為仲裁節點。
> config = {
... _id : "shard1",
... members : [
... {_id : 0, host : "10.163.97.15:27001" },
... {_id : 1, host : "10.163.97.16:27001" },
... {_id : 2, host : "10.163.97.17:27001" , arbiterOnly: true }
... ]
... }
{
"_id" : "shard1",
"members" : [
{
"_id" : 0,
"host" : "10.163.97.15:27001"
},
{
"_id" : 1,
"host" : "10.163.97.16:27001"
},
{
"_id" : 2,
"host" : "10.163.97.17:27001",
"arbiterOnly" : true
}
]
}
#初始化副本集配置
> rs.initiate(config);
{ "ok" : 1 }
設定第二個分片副本集
新增配置檔案：
[root@D2-POMS15 ~]# vi /usr/local/mongodb/conf/shard2.conf
#配置檔案內容
pidfilepath = /usr/local/mongodb/shard2/log/shard2.pid
dbpath = /usr/local/mongodb/shard2/data
logpath = /usr/local/mongodb/shard2/log/shard2.log
logappend = true
bind_ip = 0.0.0.0
port = 27002
fork = true
#開啟web監控
httpinterface=true
rest=true
#副本集名稱
replSet=shard2
#declare this is a shard db of a cluster;
shardsvr = true
#設定最大連線數
maxConns=20000
啟動三臺伺服器的shard2 server：
[root@D2-POMS15 ~]# mongod -f /usr/local/mongodb/conf/shard2.conf
about to fork child process, waiting until server is ready for connections.
forked process: 15622
child process started successfully, parent exiting
登陸一臺伺服器（不要在仲裁節點），初始化副本集
[root@D2-POMS15 ~]# mongo --port 27002
> use admin
switched to db admin
> config = {
... _id : "shard2",
... members : [
... {_id : 0, host : "10.163.97.15:27002" , arbiterOnly: true },
... {_id : 1, host : "10.163.97.16:27002" },
... {_id : 2, host : "10.163.97.17:27002" }
... ]
... }
{
"_id" : "shard2",
"members" : [
{
"_id" : 0,
"host" : "10.163.97.15:27002",
"arbiterOnly" : true
},
{
"_id" : 1,
"host" : "10.163.97.16:27002"
},
{
"_id" : 2,
"host" : "10.163.97.17:27002"
}
]
}
> rs.initiate(config);
{ "ok" : 1 }
設定第三個分片副本集
新增配置檔案：
[root@D2-POMS15 ~]# vi /usr/local/mongodb/conf/shard3.conf
#配置檔案內容
pidfilepath = /usr/local/mongodb/shard3/log/shard3.pid
dbpath = /usr/local/mongodb/shard3/data
logpath = /usr/local/mongodb/shard3/log/shard3.log
logappend = true
bind_ip = 0.0.0.0
port = 27003
fork = true
#開啟web監控
httpinterface=true
rest=true
#副本集名稱
replSet=shard3
#declare this is a shard db of a cluster;
shardsvr = true
#設定最大連線數
maxConns=20000
啟動三臺伺服器的shard3 server
[root@D2-POMS15 ~]# mongod -f /usr/local/mongodb/conf/shard3.conf
about to fork child process, waiting until server is ready for connections.
forked process: 15742
child process started successfully, parent exiting
登陸一臺伺服器（不要在仲裁節點），初始化副本集
> use admin
switched to db admin
> config = {
... _id : "shard3",
... members : [
... {_id : 0, host : "10.163.97.15:27003" },
... {_id : 1, host : "10.163.97.16:27003" , arbiterOnly: true},
... {_id : 2, host : "10.163.97.17:27003" }
... ]
... }
{
"_id" : "shard3",
"members" : [
{
"_id" : 0,
"host" : "10.163.97.15:27003"
},
{
"_id" : 1,
"host" : "10.163.97.16:27003",
"arbiterOnly" : true
},
{
"_id" : 2,
"host" : "10.163.97.17:27003"
}
]
}
> rs.initiate(config);
{ "ok" : 1 }
可以看到目前已經啟動了配置伺服器和分片伺服器。
[root@D2-POMS15 ~]# ps -ef | grep mongo | grep -v grep
root 15368 1 0 15:52 ? 00:00:07 mongod -f /usr/local/mongodb/conf/config.conf
root 15497 1 0 16:00 ? 00:00:04 mongod -f /usr/local/mongodb/conf/shard1.conf
root 15622 1 0 16:06 ? 00:00:02 mongod -f /usr/local/mongodb/conf/shard2.conf
root 15742 1 0 16:21 ? 00:00:00 mongod -f /usr/local/mongodb/conf/shard3.conf
5、配置路由伺服器 mongos
在三臺伺服器上面新增配置檔案：
[root@D2-POMS15 ~]# vi /usr/local/mongodb/conf/mongos.conf
#內容
pidfilepath = /usr/local/mongodb/mongos/log/mongos.pid
logpath = /usr/local/mongodb/mongos/log/mongos.log
logappend = true
bind_ip = 0.0.0.0
port = 20000
fork = true
#監聽的配置伺服器,只能有1個或者3個 configs為配置伺服器的副本集名字
configdb = configs/10.163.97.15:21000,10.163.97.16:21000,10.163.97.17:21000
#設定最大連線數
maxConns=20000
啟動三臺伺服器的mongos server
[root@D2-POMS15 ~]# mongos -f /usr/local/mongodb/conf/mongos.conf
about to fork child process, waiting until server is ready for connections.
forked process: 20563
child process started successfully, parent exiting
[root@D2-POMS15 ~]# mongo --port 20000
mongos> db.stats()
{
"raw" : {
"shard1/10.163.97.15:27001,10.163.97.16:27001" : {
"db" : "admin",
"collections" : 1,
"views" : 0,
"objects" : 3,
"avgObjSize" : 146.66666666666666,
"dataSize" : 440,
"storageSize" : 36864,
"numExtents" : 0,
"indexes" : 2,
"indexSize" : 65536,
"ok" : 1,
"$gleStats" : {
"lastOpTime" : Timestamp(0, 0),
"electionId" : ObjectId("7fffffff0000000000000001")
}
},
"shard2/10.163.97.16:27002,10.163.97.17:27002" : {
"db" : "admin",
"collections" : 1,
"views" : 0,
"objects" : 2,
"avgObjSize" : 114,
"dataSize" : 228,
"storageSize" : 16384,
"numExtents" : 0,
"indexes" : 2,
"indexSize" : 32768,
"ok" : 1,
"$gleStats" : {
"lastOpTime" : Timestamp(0, 0),
"electionId" : ObjectId("7fffffff0000000000000001")
}
},
"shard3/10.163.97.15:27003,10.163.97.17:27003" : {
"db" : "admin",
"collections" : 1,
"views" : 0,
"objects" : 2,
"avgObjSize" : 114,
"dataSize" : 228,
"storageSize" : 16384,
"numExtents" : 0,
"indexes" : 2,
"indexSize" : 32768,
"ok" : 1,
"$gleStats" : {
"lastOpTime" : Timestamp(0, 0),
"electionId" : ObjectId("7fffffff0000000000000002")
}
}
},
"objects" : 7,
"avgObjSize" : 127.71428571428571,
"dataSize" : 896,
"storageSize" : 69632,
"numExtents" : 0,
"indexes" : 6,
"indexSize" : 131072,
"fileSize" : 0,
"extentFreeList" : {
"num" : 0,
"totalSize" : 0
},
"ok" : 1
}
6、啟用分片
目前搭建了mongodb配置伺服器、路由伺服器，各個分片伺服器，不過應用程式連線到mongos路由伺服器並不能使用分片機制，還需要在路由伺服器裡設定分片配置，讓分片生效。
登陸任意一臺mongos
[root@D2-POMS15 ~]# mongo --port 20000
#使用admin資料庫
mongos> use admin
switched to db admin
#串聯路由伺服器與分配副本集
mongos> sh.addShard("shard1/10.163.97.15:27001,10.163.97.16:27001,10.163.97.17:27001")
{ "shardAdded" : "shard1", "ok" : 1 }
mongos> sh.addShard("shard2/10.163.97.15:27002,10.163.97.16:27002,10.163.97.17:27002")
{ "shardAdded" : "shard2", "ok" : 1 }
mongos> sh.addShard("shard3/10.163.97.15:27003,10.163.97.16:27003,10.163.97.17:27003")
{ "shardAdded" : "shard3", "ok" : 1 }
#檢視叢集狀態
mongos> sh.status()
--- Sharding Status ---
sharding version: {
"_id" : 1,
"minCompatibleVersion" : 5,
"currentVersion" : 6,
"clusterId" : ObjectId("599d34bf612249caec3fc9fe")
}
shards:
{ "_id" : "shard1", "host" : "shard1/10.163.97.15:27001,10.163.97.16:27001", "state" : 1 }
{ "_id" : "shard2", "host" : "shard2/10.163.97.16:27002,10.163.97.17:27002", "state" : 1 }
{ "_id" : "shard3", "host" : "shard3/10.163.97.15:27003,10.163.97.17:27003", "state" : 1 }
active mongoses:
"3.4.7" : 1
autosplit:
Currently enabled: yes
balancer:
Currently enabled: yes
Currently running: no
Balancer lock taken at Wed Aug 23 2017 15:54:40 GMT+0800 (CST) by ConfigServer:Balancer
Failed balancer rounds in last 5 attempts: 0
Migration Results for the last 24 hours:
No recent migrations
databases:
7、測試
目前配置服務、路由服務、分片服務、副本集服務都已經串聯起來了，但我們的目的是希望插入資料，資料能夠自動分片。連線在mongos上，準備讓指定的資料庫、指定的集合分片生效。
[root@D2-POMS15 ~]# mongo --port 20000
mongos> use admin
switched to db admin
#指定testdb分片生效
mongos> db.runCommand({enablesharding :"testdb"});
{ "ok" : 1 }
#指定資料庫裡需要分片的集合和片鍵
mongos> db.runCommand( { shardcollection : "testdb.table1",key : {id: 1} } )
{ "collectionsharded" : "testdb.table1", "ok" : 1 }
mongos> sh.status()
--- Sharding Status ---
sharding version: {
"_id" : 1,
"minCompatibleVersion" : 5,
"currentVersion" : 6,
"clusterId" : ObjectId("599d34bf612249caec3fc9fe")
}
shards:
{ "_id" : "shard1", "host" : "shard1/10.163.97.15:27001,10.163.97.16:27001", "state" : 1 }
{ "_id" : "shard2", "host" : "shard2/10.163.97.16:27002,10.163.97.17:27002", "state" : 1 }
{ "_id" : "shard3", "host" : "shard3/10.163.97.15:27003,10.163.97.17:27003", "state" : 1 }
active mongoses:
"3.4.7" : 1
autosplit:
Currently enabled: yes
balancer:
Currently enabled: yes
Currently running: no
Balancer lock taken at Wed Aug 23 2017 15:54:40 GMT+0800 (CST) by ConfigServer:Balancer
Failed balancer rounds in last 5 attempts: 0
Migration Results for the last 24 hours:
4 : Success
databases:
{ "_id" : "testdb", "primary" : "shard1", "partitioned" : true }
testdb.table1
shard key: { "id" : 1 }
unique: false
balancing: true
chunks:
shard1 1
{ "id" : { "$minKey" : 1 } } -->> { "id" : { "$maxKey" : 1 } } on : shard1 Timestamp(1, 0)
以上就是設定testdb的 table1 表需要分片，根據 id 自動分片到 shard1 ，shard2，shard3 上面去。要這樣設定是因為不是所有mongodb 的資料庫和表 都需要分片！
測試分片：
#連線mongos伺服器
[root@D2-POMS15 ~]# mongo --port 20000
#使用testdb
mongos> use testdb
switched to db testdb
#插入測試資料
mongos> for(var i=1;i<=100000;i++){db.table1.insert({id:i,"test1":"testval1"})}
WriteResult({ "nInserted" : 1 })
#檢視分片情況
mongos> sh.status()
--- Sharding Status ---
sharding version: {
"_id" : 1,
"minCompatibleVersion" : 5,
"currentVersion" : 6,
"clusterId" : ObjectId("599d34bf612249caec3fc9fe")
}
shards:
{ "_id" : "shard1", "host" : "shard1/10.163.97.15:27001,10.163.97.16:27001", "state" : 1 }
{ "_id" : "shard2", "host" : "shard2/10.163.97.16:27002,10.163.97.17:27002", "state" : 1 }
{ "_id" : "shard3", "host" : "shard3/10.163.97.15:27003,10.163.97.17:27003", "state" : 1 }
active mongoses:
"3.4.7" : 1
autosplit:
Currently enabled: yes
balancer:
Currently enabled: yes
Currently running: no
Balancer lock taken at Wed Aug 23 2017 15:54:40 GMT+0800 (CST) by ConfigServer:Balancer
Failed balancer rounds in last 5 attempts: 0
Migration Results for the last 24 hours:
6 : Success
databases:
{ "_id" : "testdb", "primary" : "shard1", "partitioned" : true }
testdb.table1
shard key: { "id" : 1 }
unique: false
balancing: true
chunks:
shard1 1
shard2 1
shard3 1
{ "id" : { "$minKey" : 1 } } -->> { "id" : 2 } on : shard2 Timestamp(2, 0)
{ "id" : 2 } -->> { "id" : 20 } on : shard3 Timestamp(3, 0)
{ "id" : 20 } -->> { "id" : { "$maxKey" : 1 } } on : shard1 Timestamp(3, 1)
可以看到這裡分片很不均衡，原因是預設的chunkSize為64M，這裡的資料量沒有達到64M，可以修改一下chunkSize的大小，方便測試：
[root@D2-POMS15 ~]# mongo --port 20000
mongos> use config
switched to db config
mongos> db.settings.save( { _id:"chunksize", value: 1 } )
WriteResult({ "nMatched" : 0, "nUpserted" : 1, "nModified" : 0, "_id" : "chunksize" })
mongos> db.settings.find();
{ "_id" : "balancer", "stopped" : false, "mode" : "full" }
{ "_id" : "chunksize", "value" : 1 }
修改後重新來測試：
mongos> use testdb
switched to db testdb
mongos> db.table1.drop();
true
mongos> use admin
switched to db admin
mongos> db.runCommand( { shardcollection : "testdb.table1",key : {id: 1} } )
{ "collectionsharded" : "testdb.table1", "ok" : 1 }
mongos> use testdb
switched to db testdb
mongos> for(var i=1;i<=100000;i++){db.table1.insert({id:i,"test1":"testval1"})}
WriteResult({ "nInserted" : 1 })
mongos> sh.status()
--- Sharding Status ---
sharding version: {
"_id" : 1,
"minCompatibleVersion" : 5,
"currentVersion" : 6,
"clusterId" : ObjectId("599d34bf612249caec3fc9fe")
}
shards:
{ "_id" : "shard1", "host" : "shard1/10.163.97.15:27001,10.163.97.16:27001", "state" : 1 }
{ "_id" : "shard2", "host" : "shard2/10.163.97.16:27002,10.163.97.17:27002", "state" : 1 }
{ "_id" : "shard3", "host" : "shard3/10.163.97.15:27003,10.163.97.17:27003", "state" : 1 }
active mongoses:
"3.4.7" : 1
autosplit:
Currently enabled: yes
balancer:
Currently enabled: yes
Currently running: no
Balancer lock taken at Wed Aug 23 2017 15:54:40 GMT+0800 (CST) by ConfigServer:Balancer
Failed balancer rounds in last 5 attempts: 0
Migration Results for the last 24 hours:
14 : Success
databases:
{ "_id" : "testdb", "primary" : "shard1", "partitioned" : true }
testdb.table1
shard key: { "id" : 1 }
unique: false
balancing: true
chunks:
shard1 4
shard2 4
shard3 3
{ "id" : { "$minKey" : 1 } } -->> { "id" : 2 } on : shard2 Timestamp(5, 1)
{ "id" : 2 } -->> { "id" : 20 } on : shard3 Timestamp(6, 1)
{ "id" : 20 } -->> { "id" : 9729 } on : shard1 Timestamp(7, 1)
{ "id" : 9729 } -->> { "id" : 21643 } on : shard1 Timestamp(3, 3)
{ "id" : 21643 } -->> { "id" : 31352 } on : shard2 Timestamp(4, 2)
{ "id" : 31352 } -->> { "id" : 43021 } on : shard2 Timestamp(4, 3)
{ "id" : 43021 } -->> { "id" : 52730 } on : shard3 Timestamp(5, 2)
{ "id" : 52730 } -->> { "id" : 64695 } on : shard3 Timestamp(5, 3)
{ "id" : 64695 } -->> { "id" : 74404 } on : shard1 Timestamp(6, 2)
{ "id" : 74404 } -->> { "id" : 87088 } on : shard1 Timestamp(6, 3)
{ "id" : 87088 } -->> { "id" : { "$maxKey" : 1 } } on : shard2 Timestamp(7, 0)
mongos> db.table1.stats()
{
"sharded" : true,
"capped" : false,
"ns" : "testdb.table1",
"count" : 100000,
"size" : 5400000,
"storageSize" : 1736704,
"totalIndexSize" : 2191360,
"indexSizes" : {
"_id_" : 946176,
"id_1" : 1245184
},
"avgObjSize" : 54,
"nindexes" : 2,
"nchunks" : 11,
"shards" : {
"shard1" : {
"ns" : "testdb.table1",
"size" : 2376864,
"count" : 44016,
"avgObjSize" : 54,
"storageSize" : 753664,
"capped" : false,
"nindexes" : 2,
"totalIndexSize" : 933888,
"indexSizes" : {
"_id_" : 405504,
"id_1" : 528384
},
"ok" : 1
},
"shard2" : {
"ns" : "testdb.table1",
"size" : 1851768,
"count" : 34292,
"avgObjSize" : 54,
"storageSize" : 606208,
"capped" : false,
"nindexes" : 2,
"totalIndexSize" : 774144,
"indexSizes" : {
"_id_" : 335872,
"id_1" : 438272
},
"ok" : 1
},
"shard3" : {
"ns" : "testdb.table1",
"size" : 1171368,
"count" : 21692,
"avgObjSize" : 54,
"storageSize" : 376832,
"capped" : false,
"nindexes" : 2,
"totalIndexSize" : 483328,
"indexSizes" : {
"_id_" : 204800,
"id_1" : 278528
},
"ok" : 1
}
},
"ok" : 1
}
可以看到現在的資料分佈就均勻多了。
８、後期運維
啟動關閉
mongodb的啟動順序是，先啟動配置伺服器，在啟動分片，最後啟動mongos.
mongod -f /usr/local/mongodb/conf/config.conf
mongod -f /usr/local/mongodb/conf/shard1.conf
mongod -f /usr/local/mongodb/conf/shard2.conf
mongod -f /usr/local/mongodb/conf/shard3.conf
mongod -f /usr/local/mongodb/conf/mongos.conf
關閉時，直接killall殺掉所有程式
killall mongod
killall mongos
參考：
http://www.cnblogs.com/ityouknow/p/7344005.html
來自 “ ITPUB部落格 ” ，連結：http://blog.itpub.net/28536251/viewspace-2144115/，如需轉載，請註明出處，否則將追究法律責任。
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