MongoDB 自动分片 auto sharding(推荐)
  5HAFzPFxGStu 2023年11月02日 67 0


MongoDB做为NoSQL数据库,最近几年持续升温,越来越多的企业都开始尝试用MongoDB代替原有Database做一些事情。MongoDB也在集群,分片,复制上也有相当不错的的表现。我通过将做各种MongoDB的部署实验进行介绍。

MongoDB 自动分片 auto sharding(推荐)_d3

第三篇 MongoDB 自动分片 auto sharding,分为6个部分

  1. 初始化文件目录
  2. 启动shard节点
  3. 配置shard节点
  4. 插入数据分片实验
  5. 删除主分片
  6. 重置主分片

系统环境介绍:

Ubuntu 12.04. LTS 64bit Server

1. 初始化文件目录

创建目录

  • config1,config2,config3是配置节点
  • shard1,shard2,shard3是分片节点


 ~ pwd
 /home/conan/dbs
 ~ mkdir config1 config2 config3 shard1 shard2 shard3
 conan@u1:~/dbs$ ls -l
 drwxrwxr-x 3 conan conan 4096 May 31 11:27 config1
 drwxrwxr-x 3 conan conan 4096 May 31 11:27 config2
 drwxrwxr-x 3 conan conan 4096 May 31 11:27 config3
 drwxrwxr-x 3 conan conan 4096 May 31 11:28 shard1
 drwxrwxr-x 3 conan conan 4096 May 31 11:29 shard2
 drwxrwxr-x 3 conan conan 4096 May 31 11:29 shard3

2. 启动shard节点

MongoDB 自动分片 auto sharding(推荐)_数据库_02

启动config节点


 ~ mongod --dbpath /home/conan/dbs/config1 --port 20001 --nojournal --fork --logpath /home/conan/dbs/config1.log
 ~ mongod --dbpath /home/conan/dbs/config2 --port 20002 --nojournal --fork --logpath /home/conan/dbs/config2.log
 ~ mongod --dbpath /home/conan/dbs/config3 --port 20003 --nojournal --fork --logpath /home/conan/dbs/config3.log


启动mongos节点


 ~ mongos --configdb localhost:20001,localhost:20002,localhost:20003 --port 30001 --fork --logpath /home/conan/dbs/mongos1.log
 ~ mongos --configdb localhost:20001,localhost:20002,localhost:20003 --port 30002 --fork --logpath /home/conan/dbs/mongos2.log


启动shard节点


 ~ mongod --dbpath /home/conan/dbs/shard1 --port 10001 --nojournal --fork --logpath /home/conan/dbs/shard1.log
 ~ mongod --dbpath /home/conan/dbs/shard2 --port 10002 --nojournal --fork --logpath /home/conan/dbs/shard2.log
 ~ mongod --dbpath /home/conan/dbs/shard3 --port 10003 --nojournal --fork --logpath /home/conan/dbs/shard3.log


查看端口


 ~ netstat -nlt
 Active Internet connections (only servers)
 Proto Recv-Q Send-Q Local Address Foreign Address State
 tcp 0 0 0.0.0.0:21003 0.0.0.0:* LISTEN
 tcp 0 0 0.0.0.0:10001 0.0.0.0:* LISTEN
 tcp 0 0 0.0.0.0:30001 0.0.0.0:* LISTEN
 tcp 0 0 0.0.0.0:10002 0.0.0.0:* LISTEN
 tcp 0 0 0.0.0.0:30002 0.0.0.0:* LISTEN
 tcp 0 0 0.0.0.0:10003 0.0.0.0:* LISTEN
 tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN
 tcp 0 0 0.0.0.0:11001 0.0.0.0:* LISTEN
 tcp 0 0 0.0.0.0:31001 0.0.0.0:* LISTEN
 tcp 0 0 0.0.0.0:11002 0.0.0.0:* LISTEN
 tcp 0 0 0.0.0.0:31002 0.0.0.0:* LISTEN
 tcp 0 0 0.0.0.0:11003 0.0.0.0:* LISTEN
 tcp 0 0 0.0.0.0:20001 0.0.0.0:* LISTEN
 tcp 0 0 0.0.0.0:20002 0.0.0.0:* LISTEN
 tcp 0 0 0.0.0.0:20003 0.0.0.0:* LISTEN
 tcp 0 0 0.0.0.0:21001 0.0.0.0:* LISTEN
 tcp 0 0 0.0.0.0:21002 0.0.0.0:* LISTEN
 tcp6 0 0 :::22 :::* LISTEN

3. 配置shard节点

连接mongos1,在mongos中添加分片:


 ~ mongo localhost:30001/admin
 MongoDB shell version: 2.4.3
 connecting to: localhost:30001/admin
 mongos> db.runCommand({addshard : "localhost:10001", allowLocal : true})
 { "shardAdded" : "shard0000", "ok" : 1 }
 mongos> db.runCommand({addshard : "localhost:10002", allowLocal : true})
 { "shardAdded" : "shard0001", "ok" : 1 }
 mongos> db.runCommand({addshard : "localhost:10003", allowLocal : true})
 { "shardAdded" : "shard0002", "ok" : 1 }

错误的语法:(MongoDB2.0.4已经不支持此语法)

mongos> db.runCommand({addshard : "shard1/localhost:10001,localhost:10002",name:"s1", allowLocal : true})
 {
 "ok" : 0,
 "errmsg" : "couldn't connect to new shard socket exception [CONNECT_ERROR] for shard1/localhost:10001,localhost:10002"
 }

查看分片信息

mongos> db.runCommand({listshards:1})
 {
 "shards" : [
 {
 "_id" : "shard0000",
 "host" : "localhost:10001"
 },
 {
 "_id" : "shard0001",
 "host" : "localhost:10002"
 },
 {
 "_id" : "shard0002",
 "host" : "localhost:10003"
 }
 ],
 "ok" : 1
 }


启用数据库分片:fensme


 mongos> db.runCommand({"enablesharding" : "fensme"})
 { "ok" : 1 }

注:一旦enable了个数据库,mongos将会把数据库里的不同数据集放在不同的分片上。只有数据集也被分片,否则一个数据集的所有数据将放在一个分片上。

启用数据集分片:fensme.users

mongos> db.runCommand({"shardcollection" : "fensme.users", "key" : {"_id" : 1,"uid":1}})
 { "collectionsharded" : "fensme.users", "ok" : 1 }

查看分片状态

mongos> db.printShardingStatus()
 --- Sharding Status ---
 sharding version: {
 "_id" : 1,
 "version" : 3,
 "minCompatibleVersion" : 3,
 "currentVersion" : 4,
 "clusterId" : ObjectId("51a8d3287034310ad2f6a94e")
 }
 shards:
 { "_id" : "shard0000", "host" : "localhost:10001" }
 { "_id" : "shard0001", "host" : "localhost:10002" }
 { "_id" : "shard0002", "host" : "localhost:10003" }
 databases:
 { "_id" : "admin", "partitioned" : false, "primary" : "config" }
 { "_id" : "fensme", "partitioned" : true, "primary" : "shard0000" }
 fensme.users

shard key: { "_id" : 1, "uid" : 1 }
chunks:
shard0000 1
{ "_id" : { "$minKey" : 1 }, "uid" : { "$minKey" : 1 } } -->> { "_id" : { "$maxKey" : 1 }, "uid" : { "$maxKey" : 1 } } on : shard0000 { "t" : 1, "i" : 0 }
fensme数据库是支持shard的,主shard是shard0000,对应host是localhost:10001

再查看config数据库

> mongos> use config
 switched to db config
 > mongos> show collections
 changelog
 chunks
 collections
 databases
 lockpings
 locks
 mongos
 settings
 shards
 system.indexes
 tags
 version
 mongos> db.shards.find()
 { "_id" : "shard0000", "host" : "localhost:10001" }
 { "_id" : "shard0001", "host" : "localhost:10002" }

{ "_id" : "shard0002", "host" : "localhost:10003" }
mongos> db.chunks.find()
{ "_id" : "fensme.users-_id_MinKey", "lastmod" : { "t" : 1, "i" : 0 }, "lastmodEpoch" : ObjectId("51a81aaa81f2196944ef40fa"), "ns" : "fensme.users", "min" : { "_id" : { "$minKey" : 1 } }, "max" : { "_id" : { "$maxKey" : 1 } }, "shard" : "shard0000" }
shards配置成功,分片信息都正确

4. 插入数据分片实验

向fensme.users插入数据, 批量插入10w条记录


 > mongos> use fensme
 switched to db fensme
 > for(var i=0; i<100000; i++){
 db.users.insert({_id:i*1597,uid:i});
 }
 > mongos> db.users.find()
 { "_id" : 10929279, "uid" : 18307 }
 { "_id" : 0, "uid" : 0 }
 { "_id" : 10929876, "uid" : 18308 }
 { "_id" : 597, "uid" : 1 }
 { "_id" : 10930473, "uid" : 18309 }
 { "_id" : 1194, "uid" : 2 }
 { "_id" : 10931070, "uid" : 18310 }
 { "_id" : 1791, "uid" : 3 }
 { "_id" : 10931667, "uid" : 18311 }
 { "_id" : 2388, "uid" : 4 }
 { "_id" : 10932264, "uid" : 18312 }
 { "_id" : 2985, "uid" : 5 }
 { "_id" : 10932861, "uid" : 18313 }
 { "_id" : 3582, "uid" : 6 }
 { "_id" : 10933458, "uid" : 18314 }
 { "_id" : 4179, "uid" : 7 }
 { "_id" : 10934055, "uid" : 18315 }
 { "_id" : 4776, "uid" : 8 }
 { "_id" : 10934652, "uid" : 18316 }
 { "_id" : 5373, "uid" : 9 }



查看数据分片存储信息


 mongos> db.users.stats()
 {
 "sharded" : true,
 "ns" : "fensme.users",
 "count" : 100000,
 "numExtents" : 12,
 "size" : 3200000,
 "storageSize" : 13983744,
 "totalIndexSize" : 6647088,
 "indexSizes" : {
 "_id_" : 2812544,
 "_id_1_uid_1" : 3834544
 },
 "avgObjSize" : 32,
 "nindexes" : 2,
 "nchunks" : 3,
 "shards" : {
 "shard0000" : {
 "ns" : "fensme.users",
 "count" : 18307,
 "size" : 585824,
 "avgObjSize" : 32,
 "storageSize" : 2793472,
 "numExtents" : 5,
 "nindexes" : 2,
 "lastExtentSize" : 2097152,
 "paddingFactor" : 1,
 "systemFlags" : 1,
 "userFlags" : 0,
 "totalIndexSize" : 1226400,
 "indexSizes" : {
 "_id_" : 523264,
 "_id_1_uid_1" : 703136
 },
 "ok" : 1
 },
 "shard0001" : {
 "ns" : "fensme.users",
 "count" : 81693,
 "size" : 2614176,
 "avgObjSize" : 32,
 "storageSize" : 11182080,
 "numExtents" : 6,
 "nindexes" : 2,
 "lastExtentSize" : 8388608,
 "paddingFactor" : 1,
 "systemFlags" : 1,
 "userFlags" : 0,
 "totalIndexSize" : 5404336,
 "indexSizes" : {
 "_id_" : 2281104,
 "_id_1_uid_1" : 3123232
 },
 "ok" : 1
 },
 "shard0002" : {
 "ns" : "fensme.users",
 "count" : 0,
 "size" : 0,
 "storageSize" : 8192,
 "numExtents" : 1,
 "nindexes" : 2,
 "lastExtentSize" : 8192,
 "paddingFactor" : 1,
 "systemFlags" : 1,
 "userFlags" : 0,
 "totalIndexSize" : 16352,
 "indexSizes" : {
 "_id_" : 8176,
 "_id_1_uid_1" : 8176
 },
 "ok" : 1
 }
 },
 "ok" : 1
 }



查看users数据集信息,shard0000上面18307条,shard0001上面81693条,shard0002上面没有数据。分片很不均匀。

分别连接到shard1,shard2,shard3查看数据分片存储的情况
连接shard1


 mongo localhost:10001
 MongoDB shell version: 2.4.3
 connecting to: localhost:10001/test
 > show dbs
 fensme 0.203125GB
 local 0.078125GB
 > use fensme
 switched to db fensme
 > show collections
 system.indexes
 users
 > db.users.count()
 18307



连接shard2, 81693条记录

 mongo localhost:10002
 MongoDB shell version: 2.4.3
 connecting to: localhost:10002/test
 > use fensme
 switched to db fensme
 > db.users.count()
 81693

连接shard3,无数据


 mongo localhost:10003
 MongoDB shell version: 2.4.3
 connecting to: localhost:10002/test
 > use fensme
 switched to db fensme
 > db.users.count()
 0



注:分片数据分配不均匀,应该重新规化分片的key。

5. 删除主分片

移除Primary分片shard1,localhost:10001


 > use admin
 mongos> db.runCommand({"removeshard":"localhost:10001"})
 {
 "msg" : "draining started successfully",
 "state" : "started",
 "shard" : "shard0000",
 "note" : "you need to drop or movePrimary these databases",
 "dbsToMove" : [
 "fensme"
 ],
 "ok" : 1
 }



提示shard0000是主分片,要手动迁移主分片。

查看分片状态


 mongos> db.runCommand({listshards:1})
 {
 "shards" : [
 {
 "_id" : "shard0001",
 "host" : "localhost:10002"
 },
 {
 "_id" : "shard0002",
 "host" : "localhost:10003"
 },
 {
 "_id" : "shard0000",
 "draining" : true,
 "host" : "localhost:10001"
 }
 ],
 "ok" : 1
 }



draining为正在迁移过程中。。。。


 mongos> db.printShardingStatus()
 --- Sharding Status ---
 sharding version: {
 "_id" : 1,
 "version" : 3,
 "minCompatibleVersion" : 3,
 "currentVersion" : 4,
 "clusterId" : ObjectId("51a8d3287034310ad2f6a94e")
 }
 shards:
 { "_id" : "shard0000", "draining" : true, "host" : "localhost:10001" }
 { "_id" : "shard0001", "host" : "localhost:10002" }
 { "_id" : "shard0002", "host" : "localhost:10003" }
 databases:
 { "_id" : "admin", "partitioned" : false, "primary" : "config" }
 { "_id" : "fensme", "partitioned" : true, "primary" : "shard0000" }
 fensme.users
 shard key: { "_id" : 1, "uid" : 1 }
 chunks:
 shard0002 1
 shard0001 2
 { "_id" : { "$minKey" : 1 }, "uid" : { "$minKey" : 1 } } -->> { "_id" : 0, "uid" : 0 } on shard0002 { "t" : 3, "i" : 0 }
 { "_id" : 0, "uid" : 0 } -->> { "_id" : 10929279, "uid" : 18307 } on : shard0001 { "t" : 4 "i" : 0 }
 { "_id" : 10929279, "uid" : 18307 } -->> { "_id" : { "$maxKey" : 1 }, "uid" : { "$maxKey" 1 } } on : shard0001 { "t" : 2, "i" : 0 }

 draining为正在迁移过程中。。。。

查看db.users的分片存储分布


 > use fensme
 mongos> db.users.stats()
 {
 "sharded" : true,
 "ns" : "fensme.users",
 "count" : 118307,
 "numExtents" : 12,
 "size" : 3785824,
 "storageSize" : 13983744,
 "totalIndexSize" : 8854608,
 "indexSizes" : {
 "_id_" : 3752784,
 "_id_1_uid_1" : 5101824
 },
 "avgObjSize" : 32,
 "nindexes" : 2,
 "nchunks" : 3,
 "shards" : {
 "shard0000" : {
 "ns" : "fensme.users",
 "count" : 18307,
 "size" : 585824,
 "avgObjSize" : 32,
 "storageSize" : 2793472,
 "numExtents" : 5,
 "nindexes" : 2,
 "lastExtentSize" : 2097152,
 "paddingFactor" : 1,
 "systemFlags" : 1,
 "userFlags" : 0,
 "totalIndexSize" : 1226400,
 "indexSizes" : {
 "_id_" : 523264,
 "_id_1_uid_1" : 703136
 },
 "ok" : 1
 },
 "shard0001" : {
 "ns" : "fensme.users",
 "count" : 100000,
 "size" : 3200000,
 "avgObjSize" : 32,
 "storageSize" : 11182080,
 "numExtents" : 6,
 "nindexes" : 2,
 "lastExtentSize" : 8388608,
 "paddingFactor" : 1,
 "systemFlags" : 1,
 "userFlags" : 0,
 "totalIndexSize" : 7611856,
 "indexSizes" : {
 "_id_" : 3221344,
 "_id_1_uid_1" : 4390512
 },
 "ok" : 1
 },
 "shard0002" : {
 "ns" : "fensme.users",
 "count" : 0,
 "size" : 0,
 "storageSize" : 8192,
 "numExtents" : 1,
 "nindexes" : 2,
 "lastExtentSize" : 8192,
 "paddingFactor" : 1,
 "systemFlags" : 1,
 "userFlags" : 0,
 "totalIndexSize" : 16352,
 "indexSizes" : {
 "_id_" : 8176,
 "_id_1_uid_1" : 8176
 },
 "ok" : 1
 }
 },
 "ok" : 1
 }



发现shard0000的数据,都被自动迁移到了shard0001

连接node2,发现10W条数据全在这里。

mongo localhost:10002
 MongoDB shell version: 2.4.3
 connecting to: localhost:10002/test
 > use fensme
 switched to db fensme
 > db.users.count()
 100000

6. 重置主分片

重新设置主分片为shard0002


 mongos> use admin
 switched to db admin
 mongos> db.runCommand({"moveprimary":"fensme","to":"localhost:10003"})
 { "primary " : "shard0002:localhost:10003", "ok" : 1 }

再次删除node1, shard0000

use admin
 mongos> db.runCommand({"removeshard":"localhost:10001"})
 {
 "msg" : "removeshard completed successfully",
 "state" : "completed",
 "shard" : "shard0000",
 "ok" : 1
 }

删除分片成功。

查看分片信息

mongos> db.printShardingStatus()
 --- Sharding Status ---
 sharding version: {
 "_id" : 1,
 "version" : 3,
 "minCompatibleVersion" : 3,
 "currentVersion" : 4,
 "clusterId" : ObjectId("51a8e8b8bf1411b5099da477")
 }
 shards:
 { "_id" : "shard0001", "host" : "localhost:10002" }
 { "_id" : "shard0002", "host" : "localhost:10003" }
 databases:
 { "_id" : "admin", "partitioned" : false, "primary" : "config" }
 { "_id" : "fensme", "partitioned" : true, "primary" : "shard0002" }
 fensme.users
 shard key: { "_id" : 1, "uid" : 1 }
 chunks:
 shard0002 1
 shard0001 2
 { "_id" : { "$minKey" : 1 }, "uid" : { "$minKey" : 1 } } -->> { "_id" : 0, "uid" : 0 } on : shard0002 { "t" : 3, "i" : 0 }
 { "_id" : 0, "uid" : 0 } -->> { "_id" : 29236279, "uid" : 18307 } on : shard0001 { "t" : 4, "i" : 0 }
 { "_id" : 29236279, "uid" : 18307 } -->> { "_id" : { "$maxKey" : 1 }, "uid" : { "$maxKey" : 1 } } on : shard0001 { "t" : 2, "i" : 0 }

fensme的数据库的primary分片,成功的改为了shard0002.

再看数据的分布情况:


 mongos> use fensme
 switched to db fensme
 mongos> db.users.stats()
 {
 "sharded" : true,
 "ns" : "fensme.users",
 "count" : 100000,
 "numExtents" : 7,
 "size" : 3200000,
 "storageSize" : 11190272,
 "totalIndexSize" : 7628208,
 "indexSizes" : {
 "_id_" : 3229520,
 "_id_1_uid_1" : 4398688
 },
 "avgObjSize" : 32,
 "nindexes" : 2,
 "nchunks" : 3,
 "shards" : {
 "shard0001" : {
 "ns" : "fensme.users",
 "count" : 100000,
 "size" : 3200000,
 "avgObjSize" : 32,
 "storageSize" : 11182080,
 "numExtents" : 6,
 "nindexes" : 2,
 "lastExtentSize" : 8388608,
 "paddingFactor" : 1,
 "systemFlags" : 1,
 "userFlags" : 0,
 "totalIndexSize" : 7611856,
 "indexSizes" : {
 "_id_" : 3221344,
 "_id_1_uid_1" : 4390512
 },
 "ok" : 1
 },
 "shard0002" : {
 "ns" : "fensme.users",
 "count" : 0,
 "size" : 0,
 "storageSize" : 8192,
 "numExtents" : 1,
 "nindexes" : 2,
 "lastExtentSize" : 8192,
 "paddingFactor" : 1,
 "systemFlags" : 1,
 "userFlags" : 0,
 "totalIndexSize" : 16352,
 "indexSizes" : {
 "_id_" : 8176,
 "_id_1_uid_1" : 8176
 },
 "ok" : 1
 }
 },
 "ok" : 1
 }

shard0001包括全部10W条数据,shard0002没有数据,shard0000已经不存储



【版权声明】本文内容来自摩杜云社区用户原创、第三方投稿、转载,内容版权归原作者所有。本网站的目的在于传递更多信息,不拥有版权,亦不承担相应法律责任。如果您发现本社区中有涉嫌抄袭的内容,欢迎发送邮件进行举报,并提供相关证据,一经查实,本社区将立刻删除涉嫌侵权内容,举报邮箱: cloudbbs@moduyun.com

  1. 分享:
最后一次编辑于 2023年11月08日 0

暂无评论

推荐阅读
5HAFzPFxGStu