概念：
MongoDB分片是使用多個伺服器儲存資料的方法，以支援巨大的資料儲存和對資料進行儲存
優勢：
1、減少了每個分片需啊喲處理的請求數，群集可以提高自己的儲存容量和吞吐量
2、減少了每個分片儲存的資料
三個主要元件：
shard：分片伺服器，用於儲存實際的資料塊，由多臺伺服器組成一個複製集承擔，防止主機單點故障
config server：配置伺服器，儲存整個分片群集的配置資訊，包括塊資訊
routers：前端路由，客戶端由此進入，讓整個群集看上去像單一資料庫如何部署MongoDB分片群集！！！
1、安裝MongoDB3.2版本包和openssl-devel包
[root@localhost ~]# yum install openssl-devel -y
[root@localhost ~]# mkdir /abc
[root@localhost ~]# mount.cifs //192.168.200.1/orc /abc
Password for root@//192.168.200.1/orc:
[root@localhost ~]# cd /abc
[root@localhost abc]# ls
mongodb-linux-x86_64-3.2.1.tgz //MongoDB 3.2版本
[root@localhost abc]# tar zxvf mongodb-linux-x86_64-3.2.1.tgz -C /opt
[root@localhost abc]# cd /opt
[root@localhost opt]# ls
mongodb-linux-x86_64-3.2.1 rh
[root@localhost opt]# mv mongodb-linux-x86_64-3.2.1/ /usr/local/mongodb
[root@localhost opt]# cd /usr/local/bin/
[root@localhost bin]# ln -s /usr/local/mongodb/bin/mongo /usr/bin/mongo //建立軟連線
[root@localhost bin]# ln -s /usr/local/mongodb/bin/mongod /usr/bin/mongod
[root@localhost bin]# mkdir -p /data/mongodb/mongodb{1,2,3,4}
[root@localhost bin]# mkdir /data/mongodb/logs
[root@localhost bin]# touch /data/mongodb/logs/mongodb{1,2,3,4}.log
[root@localhost bin]# chmod -R 777 /data/mongodb/logs/*.log
[root@localhost bin]# ulimit -n 25000 //開啟檔案數量
[root@localhost bin]# ulimit -u 25000 //程式併發數2、部署配置伺服器
編輯mongodb1.conf配置檔案，埠為37017，設定configsvr=true，啟動配置伺服器
[root@localhost bin]# vim mongodb1.con
port=37017
dbpath=/data/mongodb/mongodb1
logpath=/data/mongodb/logs/mongodb1.log
logappend=true
fork=true
maxConns=5000
storageEngine=mmapv1
configsvr=true //開啟配置伺服器3、某節點記憶體不足，從其它節點分配記憶體
[root@localhost bin]# sysctl -w vm.zone_reclaim_mode=0
vm.zone_reclaim_mode = 0
[root@localhost bin]# echo never > /sys/kernel/mm/transparent_hugepage/enabled
[root@localhost bin]# echo never > /sys/kernel/mm/transparent_hugepage/defrag
[root@localhost bin]# mongod -f mongodb1.conf
about to fork child process, waiting until server is ready for connections.
forked process: 6895
child process started successfully, parent exiting4、部署分片伺服器
編輯mongodb2.conf配置檔案，埠為47017，設定shardsvr=true；編輯mongodb3.conf配置檔案，埠為47018，啟動兩個分片伺服器
[root@localhost bin]# cp -p mongodb1.conf mongodb2.conf
[root@localhost bin]# vim mongodb2.conf
port=47017 //修改埠
dbpath=/data/mongodb/mongodb2
logpath=/data/mongodb/logs/mongodb2.log
logappend=true
fork=true
maxConns=5000
storageEngine=mmapv1
shardsvr=true //開啟分片伺服器
[root@localhost bin]# cp -p mongodb2.conf mongodb3.conf
[root@localhost bin]# vim mongodb3.conf
port=47018
dbpath=/data/mongodb/mongodb3
logpath=/data/mongodb/logs/mongodb3.log
logappend=true
fork=true
maxConns=5000
storageEngine=mmapv1
shardsvr=true
[root@localhost bin]# mongod -f mongodb2.conf
about to fork child process, waiting until server is ready for connections.
forked process: 7080
child process started successfully, parent exiting
[root@localhost bin]# mongod -f mongodb3.conf
about to fork child process, waiting until server is ready for connections.
forked process: 7107
child process started successfully, parent exiting
[root@localhost bin]# netstat -antp | grep mongod
tcp 0 0 0.0.0.0:37017 0.0.0.0:* LISTEN god
tcp 0 0 0.0.0.0:47017 0.0.0.0:* LISTEN god
tcp 0 0 0.0.0.0:47018 0.0.0.0:* LISTEN god 5、啟動路由伺服器
./mongos –help命令可以檢視路由相關引數資訊。chunkSize為資料塊大小，預設為200M，這裡將值設為1
[root@localhost bin]# ./mongos --port 27017 --fork --logpath=/usr/local/mongodb/bin/route.log --configdb 192.168.200.142:37017 --chunkSize 16、啟用分片伺服器
mongos> sh.addShard("192.168.200.142:47017")
{ "shardAdded" : "shard0000", "ok" : 1 }
mongos> sh.addShard("192.168.200.142:47018")
{ "shardAdded" : "shard0001", "ok" : 1 }
mongos> sh.status()
--- Sharding Status ---
sharding version: {
"_id" : 1,
"minCompatibleVersion" : 5,
"currentVersion" : 6,
"clusterId" : ObjectId("5b4f68599dcf397cc4e7c598")
}
shards: //分片伺服器開啟
{ "_id" : "shard0000", "host" : "192.168.200.142:47017" }
{ "_id" : "shard0001", "host" : "192.168.200.142:47018" }
active mongoses:
"3.2.1" : 1
balancer:
Currently enabled: yes
Currently running: no
Failed balancer rounds in last 5 attempts: 0
Migration Results for the last 24 hours:
No recent migratio7、分片功能
[root@localhost bin]# mongo
mongos> use school
switched to db school
mongos> for(var i=1;i<=10000;i++)db.users.insert({"id":i,"name":"jack"+i})
WriteResult({ "nInserted" : 1 })
mongos> show dbs
config 0.031GB
school 0.078GB
mongos> use school
switched to db school
mongos> show collections
system.indexes
users
mongos> db.users.find().limit(10) //檢視頭十行內容
{ "_id" : ObjectId("5b4f6a24ef33d588c0dbc4ae"), "id" : 1, "name" : "jack1" }
{ "_id" : ObjectId("5b4f6a24ef33d588c0dbc4af"), "id" : 2, "name" : "jack2" }
{ "_id" : ObjectId("5b4f6a24ef33d588c0dbc4b0"), "id" : 3, "name" : "jack3" }
{ "_id" : ObjectId("5b4f6a24ef33d588c0dbc4b1"), "id" : 4, "name" : "jack4" }
{ "_id" : ObjectId("5b4f6a24ef33d588c0dbc4b2"), "id" : 5, "name" : "jack5" }
{ "_id" : ObjectId("5b4f6a24ef33d588c0dbc4b3"), "id" : 6, "name" : "jack6" }
{ "_id" : ObjectId("5b4f6a24ef33d588c0dbc4b4"), "id" : 7, "name" : "jack7" }
{ "_id" : ObjectId("5b4f6a24ef33d588c0dbc4b5"), "id" : 8, "name" : "jack8" }
{ "_id" : ObjectId("5b4f6a24ef33d588c0dbc4b6"), "id" : 9, "name" : "jack9" }
{ "_id" : ObjectId("5b4f6a24ef33d588c0dbc4b7"), "id" : 10, "name" : "jack10" }
mongos> sh.status() //檢視資料庫分片資訊
--- Sharding Status ---
sharding version: {
"_id" : 1,
"minCompatibleVersion" : 5,
"currentVersion" : 6,
"clusterId" : ObjectId("5b4f68599dcf397cc4e7c598")
}
shards:
{ "_id" : "shard0000", "host" : "192.168.200.142:47017" }
{ "_id" : "shard0001", "host" : "192.168.200.142:47018" }
active mongoses:
"3.2.1" : 1
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:
{ "_id" : "school", "primary" : "shard0000", "partitioned" : false }
mongos> sh.enableSharding("school") //啟用資料庫分片
{ "ok" : 1 }
mongos> sh.status()
--- Sharding Status ---
sharding version: {
"_id" : 1,
"minCompatibleVersion" : 5,
"currentVersion" : 6,
"clusterId" : ObjectId("5b4f68599dcf397cc4e7c598")
}
shards:
{ "_id" : "shard0000", "host" : "192.168.200.142:47017" }
{ "_id" : "shard0001", "host" : "192.168.200.142:47018" }
active mongoses:
"3.2.1" : 1
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:
{ "_id" : "school", "primary" : "shard0000", "partitioned" : true }
mongos> db.users.createIndex({"id":1}) //對users表建立索引
{
"raw" : {
"192.168.200.142:47017" : {
"createdCollectionAutomatically" : false,
"numIndexesBefore" : 1,
"numIndexesAfter" : 2,
"ok" : 1
}
},
"ok" : 1
}
mongos> sh.shardCollection("school.users",{"id":1})//表分片
{ "collectionsharded" : "school.users", "ok" : 1 }
mongos> sh.status()
--- Sharding Status ---
sharding version: {
"_id" : 1,
"minCompatibleVersion" : 5,
"currentVersion" : 6,
"clusterId" : ObjectId("5b4f68599dcf397cc4e7c598")
}
shards:
{ "_id" : "shard0000", "host" : "192.168.200.142:47017" }
{ "_id" : "shard0001", "host" : "192.168.200.142:47018" }
active mongoses:
"3.2.1" : 1
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:
{ "_id" : "school", "primary" : "shard0000", "partitioned" : true }
school.users
shard key: { "id" : 1 }
unique: false
balancing: true
chunks:
shard0000 3
{ "id" : { "$minKey" : 1 } } -->> { "id" : 4682 } on : shard0000 Timestamp(1, 0)
{ "id" : 4682 } -->> { "id" : 9364 } on : shard0000 Timestamp(1, 1)
{ "id" : 9364 } -->> { "id" : { "$maxKey" : 1 } } on : shard0000 Timestamp(1, 2) //分片成功