[ MongoDB ] 分片集羣及測試

分片

在Mongodb裏面存在另外一種集羣,就是分片技術,能夠知足MongoDB數據量大量增加的需求。

當MongoDB存儲海量的數據時,一臺機器可能不足以存儲數據,也可能不足以提供可接受的讀寫吞吐量。這時,咱們就能夠經過在多臺機器上分割數據,使得數據庫系統能存儲和處理更多的數據。

爲何使用分片?

    1. 複製全部的寫入操做到主節點
    2. 延遲的敏感數據會在主節點查詢
    3. 單個副本集限制在12個節點
    4. 當請求量巨大時會出現內存不足。
    5. 本地磁盤不足
    6. 垂直擴展價格昂貴

前端

Shard:
    用於存儲實際的數據塊,實際生產環境中一個shard server角色可由幾臺機器組個一個relica set承擔,防止主機單點故障

Config Server:
    mongod實例,存儲了整個 ClusterMetadata,其中包括 chunk信息。

Query Routers:
    前端路由,客戶端由此接入,且讓整個集羣看上去像單一數據庫,前端應用能夠透明使用。node

分片實例:
    node1:10.0.0.10 -- 3個Config Server、1個Routers、1個Shard
    node2:10.0.0.11 -- 1個Routers、1個Shard
    node3:10.0.0.12 -- 1個Shard

注意:在作分片的時候,要避免Shard在同一臺主機上,這樣就沒辦法實現分片。mongodb

 

node1 配置以下:


三個Shard 的配置文件:數據庫

[root@node1 conf]# ls
mongosvr-20000.conf  mongosvr-21000.conf  mongosvr-22000.conf
[root@node1 conf]# vim mongosvr-20000.conf 

systemLog:
 destination: file
###日誌存儲位置
 path: /mongodb/logs/mongosvr-20000.log
 logAppend: true
storage:
##journal配置
 journal:
  enabled: true
##數據文件存儲位置
 dbPath: /mongodb/data/mongosvr-20000
##是否一個庫一個文件夾
 directoryPerDB: true
##數據引擎
 engine: wiredTiger
##WT引擎配置
 wiredTiger:
  engineConfig:
##WT最大使用cache(根據服務器實際狀況調節)
   cacheSizeGB: 10
##是否將索引也按數據庫名單獨存儲
   directoryForIndexes: true
##表壓縮配置
  collectionConfig:
   blockCompressor: zlib
##索引配置
  indexConfig:
   prefixCompression: true
processManagement:
 fork: true  # fork and run in background
 pidFilePath: /mongodb/socket/mongodsvr-20000.pid
##端口配置
net:
 port: 20000
 bindIp: 10.0.0.10
sharding:
 clusterRole: configsvr

# 啓動config服務
[root@node1 ~]# mongod -f /mongodb/conf/mongosvr-20000.conf 
about to fork child process, waiting until server is ready for connections.
forked process: 1934
child process started successfully, parent exiting


[root@node1 conf]# netstat -ntplu | grep mongod
tcp        0      0 10.0.0.10:20000             0.0.0.0:*                   LISTEN      1934/mongod         
tcp        0      0 10.0.0.10:21000             0.0.0.0:*                   LISTEN      1960/mongod         
tcp        0      0 10.0.0.10:22000             0.0.0.0:*                   LISTEN      1990/mongod 

建立mongos服務vim

[root@node1 conf]# vim mongos-30000.conf 

systemLog:
 destination: file
###日誌存儲位置
 path: /mongodb/logs/mongos-30000.log
 logAppend: true
processManagement:
 fork: true  # fork and run in background
 pidFilePath: /mongodb/socket/mongos-30000.pid
##端口配置
net:
 port: 30000
 bindIp: 10.0.0.10

## 將confige server 添加到路由
sharding:
 configDB: 10.0.0.10:20000,10.0.0.10:21000,10.0.0.10:22000

啓動路由服務服務器

[root@node1 conf]# mongos -f /mongodb/conf/mongos-30000.conf 
about to fork child process, waiting until server is ready for connections.
forked process: 2022
child process started successfully, parent exiting

[root@node1 conf]# netstat -ntplu | grep mongos
tcp        0      0 10.0.0.10:30000             0.0.0.0:*                   LISTEN      2022/mongos 

在開啓一個Shard服務socket

配置:
[root@node1 conf]# ls
mongod-40000.conf  mongos-30000.conf  mongosvr-20000.conf  mongosvr-21000.conf  mongosvr-22000.conf
[root@node1 conf]# vim mongod-40000.conf 

systemLog:
 destination: file
###日誌存儲位置
 path: /mongodb/logs/mongod-40000.log
 logAppend: true
storage:
##journal配置
 journal:
  enabled: true
##數據文件存儲位置
 dbPath: /mongodb/data/mongod-40000
##是否一個庫一個文件夾
 directoryPerDB: true
##數據引擎
 engine: wiredTiger
##WT引擎配置
 wiredTiger:
  engineConfig:
##WT最大使用cache(根據服務器實際狀況調節)
   cacheSizeGB: 10
##是否將索引也按數據庫名單獨存儲
   directoryForIndexes: true
##表壓縮配置
  collectionConfig:
   blockCompressor: zlib
##索引配置
  indexConfig:
   prefixCompression: true
processManagement:
 fork: true  # fork and run in background
 pidFilePath: /mongodb/socket/mongod-40000.pid
##端口配置
net:
 port: 40000
 bindIp: 10.0.0.10


# 啓動Shard服務

[root@node1 conf]# mongod -f /mongodb/conf/mongod-40000.conf 
about to fork child process, waiting until server is ready for connections.
forked process: 2184
child process started successfully, parent exiting

node1 節點服務配置完畢。tcp




node2 配置1個router、1個Shard
node3 配置1個Shard

配置如同node1同樣,這裏不在貼代碼。ui

node1:
[root@node1 ~]# netstat -ntplu | grep mongo.
tcp        0      0 10.0.0.10:40000             0.0.0.0:*                   LISTEN      2184/mongod         
tcp        0      0 10.0.0.10:20000             0.0.0.0:*                   LISTEN      1934/mongod         
tcp        0      0 10.0.0.10:21000             0.0.0.0:*                   LISTEN      1960/mongod         
tcp        0      0 10.0.0.10:30000             0.0.0.0:*                   LISTEN      2022/mongos         
tcp        0      0 10.0.0.10:22000             0.0.0.0:*                   LISTEN      1990/mongod

node2:
[root@node2 ~]# netstat -ntplu | grep mongo.
tcp        0      0 10.0.0.11:40000             0.0.0.0:*                   LISTEN      1851/mongod         
tcp        0      0 10.0.0.11:30000             0.0.0.0:*                   LISTEN      1923/mongos

node3:
[root@node3 ~]# netstat -ntplu | grep mongo.
tcp        0      0 10.0.0.12:40000             0.0.0.0:*                   LISTEN      1927/mongod 

 

接下來須要在node1上進行分片的配置:spa

[root@node1 ~]# mongo 10.0.0.10:30000

mongos> sh.status()
--- Sharding Status --- 
  sharding version: {
    "_id" : 1,
    "minCompatibleVersion" : 5,
    "currentVersion" : 6,
    "clusterId" : ObjectId("57b1addb0a3c54686427f812")
}
  shards:            # 目前尚未節點加入到分片中
  active mongoses:
    "3.2.8" : 2
  balancer:
    Currently enabled:  yes
    Currently running:  no
    Failed balancer rounds in last 5 attempts:  0
    Migration Results for the last 24 hours: 
        No recent migrations
  databases:


# 添加新的分片
mongos> sh.addShard('10.0.0.10:40000')
{ "shardAdded" : "shard0000", "ok" : 1 }
mongos> sh.addShard('10.0.0.11:40000')
{ "shardAdded" : "shard0001", "ok" : 1 }
mongos> sh.addShard('10.0.0.12:40000')
{ "shardAdded" : "shard0002", "ok" : 1 }



mongos> sh.status()
--- Sharding Status --- 
  sharding version: {
    "_id" : 1,
    "minCompatibleVersion" : 5,
    "currentVersion" : 6,
    "clusterId" : ObjectId("57b1addb0a3c54686427f812")
}
  shards:        # 這裏就能夠看到剛纔添加的三個Shard節點
    {  "_id" : "shard0000",  "host" : "10.0.0.10:40000" }
    {  "_id" : "shard0001",  "host" : "10.0.0.11:40000" }
    {  "_id" : "shard0002",  "host" : "10.0.0.12:40000" }
  active mongoses:
    "3.2.8" : 2
  balancer:
    Currently enabled:  yes
    Currently running:  no
    Failed balancer rounds in last 5 attempts:  0
    Migration Results for the last 24 hours: 
        No recent migrations
  databases:

注意:分片的功能是須要手動開啓才能實現的:sh.enableSharding("庫名")、sh.shardCollection("庫名.集合名",{"key":1})

mongos> sh.enableSharding('testdb')
{ "ok" : 1 }
mongos> sh.shardCollection('testdb.users',{uid:1})
{ "collectionsharded" : "testdb.users", "ok" : 1 }
mongos> show dbs
config  0.001GB
testdb  0.000GB
mongos> use testdb
switched to db testdb
mongos> for(i=1;i<=200000;i++) db.users.insert({uid:i,name:'hukey',age:23})  # 生成20W條數據,而且經過uid來進行分片
WriteResult({ "nInserted" : 1 })

# 分片的規則是自動分裂和平衡。

數據生成完畢,咱們能夠經過node2的router服務登陸上去查看。

mongos> db.users.count()
200000
mongos> sh.status()
--- Sharding Status --- 
  sharding version: {
    "_id" : 1,
    "minCompatibleVersion" : 5,
    "currentVersion" : 6,
    "clusterId" : ObjectId("57b1addb0a3c54686427f812")
}
  shards:
    {  "_id" : "shard0000",  "host" : "10.0.0.10:40000" }
    {  "_id" : "shard0001",  "host" : "10.0.0.11:40000" }
    {  "_id" : "shard0002",  "host" : "10.0.0.12:40000" }
  active mongoses:
    "3.2.8" : 2
  balancer:
    Currently enabled:  yes
    Currently running:  no
    Failed balancer rounds in last 5 attempts:  0
    Migration Results for the last 24 hours: 
        2 : Success
  databases:
    {  "_id" : "testdb",  "primary" : "shard0000",  "partitioned" : true }
        testdb.users
            shard key: { "uid" : 1 }
            unique: false
            balancing: true
            chunks:                # 這裏能夠查看到平均分片到每一個Shard上。
                shard0000    1
                shard0001    1
                shard0002    1
            { "uid" : { "$minKey" : 1 } } -->> { "uid" : 2 } on : shard0001 Timestamp(2, 0) 
            { "uid" : 2 } -->> { "uid" : 18 } on : shard0002 Timestamp(3, 0) 
            { "uid" : 18 } -->> { "uid" : { "$maxKey" : 1 } } on : shard0000 Timestamp(3, 1)

mongodb是用來存儲海量數據的,因此20W分片可能不是特別明顯,能夠每次增長10W條來查看。

            chunks:
                shard0000    3
                shard0001    2
                shard0002    2
            { "uid" : { "$minKey" : 1 } } -->> { "uid" : 2 } on : shard0001 Timestamp(2, 0) 
            { "uid" : 2 } -->> { "uid" : 18 } on : shard0002 Timestamp(3, 0) 
            { "uid" : 18 } -->> { "uid" : 26232 } on : shard0002 Timestamp(5, 0) 
            { "uid" : 26232 } -->> { "uid" : 59000 } on : shard0000 Timestamp(5, 1) 
            { "uid" : 59000 } -->> { "uid" : 65554 } on : shard0000 Timestamp(4, 4) 
            { "uid" : 65554 } -->> { "uid" : 200000 } on : shard0000 Timestamp(3, 3) 
            { "uid" : 200000 } -->> { "uid" : { "$maxKey" : 1 } } on : shard0001 Timestamp(4, 0)

    這樣,就很明顯了。分片集羣搭建完畢,可是目前全部節點都是單點,一旦故障就形成很嚴重的後果,所以須要將分片和副本集聯合起來用,才能實現高可用。

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