分片整体信息

mongos> sh.status()
--- Sharding Status --- 
  sharding version: {
    "_id" : 1,
    "minCompatibleVersion" : 5,
    "currentVersion" : 6,
    "clusterId" : ObjectId("60545017224c766911a9c440")
  }
  shards:
        {  "_id" : "hdshard1",  "host" : "hdshard1/172.16.254.136:40001,172.16.254.137:40001,172.16.254.138:40001",  "state" : 1 }
        {  "_id" : "hdshard2",  "host" : "hdshard2/172.16.254.136:40002,172.16.254.137:40002,172.16.254.138:40002",  "state" : 1 }
        {  "_id" : "hdshard3",  "host" : "hdshard3/172.16.254.136:40003,172.16.254.137:40003,172.16.254.138:40003",  "state" : 1 }
  active mongoses:
        "4.2.12" : 3
  autosplit:
        Currently enabled: yes
  balancer:
        Currently enabled:  yes
        Currently running:  no
        Failed balancer rounds in last 5 attempts:  5
        Last reported error:  Could not find host matching read preference { mode: "primary" } for set hdshard2
        Time of Reported error:  Wed Apr 14 2021 19:16:07 GMT+0800 (CST)
        Migration Results for the last 24 hours: 
                No recent migrations
  databases:
        {  "_id" : "config",  "primary" : "config",  "partitioned" : true }
                config.system.sessions
                        shard key: { "_id" : 1 }
                        unique: false
                        balancing: true
                        chunks:
                                hdshard1    342
                                hdshard2    341
                                hdshard3    341
                        too many chunks to print, use verbose if you want to force print
        {  "_id" : "db5",  "primary" : "hdshard2",  "partitioned" : true,  "version" : {  "uuid" : UUID("bc5d26af-5248-431b-8065-7143fdbffb97"),  "lastMod" : 1 } }
                db5.db5
                        shard key: { "id" : 1 }
                        unique: false
                        balancing: true
                        chunks:
                                hdshard2    1
                        { "id" : { "$minKey" : 1 } } -->> { "id" : { "$maxKey" : 1 } } on : hdshard2 Timestamp(1, 0) 
        {  "_id" : "db6",  "primary" : "hdshard3",  "partitioned" : false,  "version" : {  "uuid" : UUID("6a1dd60f-a1fc-47be-9fad-d8ce01841d68"),  "lastMod" : 1 } }
        {  "_id" : "recommend",  "primary" : "hdshard1",  "partitioned" : false,  "version" : {  "uuid" : UUID("cb833b8e-cc4f-4c52-83c3-719aa383bac4"),  "lastMod" : 1 } }

列出分片信息

mongos> use admin
switched to db admin
mongos> db.runCommand( { listshards : 1 } )
{
    "shards" : [
        {
            "_id" : "hdshard1",
            "host" : "hdshard1/172.16.254.136:40001,172.16.254.137:40001,172.16.254.138:40001",
            "state" : 1
        },
        {
            "_id" : "hdshard2",
            "host" : "hdshard2/172.16.254.136:40002,172.16.254.137:40002,172.16.254.138:40002",
            "state" : 1
        },
        {
            "_id" : "hdshard3",
            "host" : "hdshard3/172.16.254.136:40003,172.16.254.137:40003,172.16.254.138:40003",
            "state" : 1
        }
    ],
    "ok" : 1,
    "operationTime" : Timestamp(1618479240, 1),
    "$clusterTime" : {
        "clusterTime" : Timestamp(1618479240, 1),
        "signature" : {
            "hash" : BinData(0,"ou1dzkqck0XTgvqkH/xBlhXC0R4="),
            "keyId" : NumberLong("6941260985399246879")
        }
    }
}

或者

mongos> use config
switched to db config
mongos> db.shards.find()
{ "_id" : "hdshard1", "host" : "hdshard1/172.16.254.136:40001,172.16.254.137:40001,172.16.254.138:40001", "state" : 1 }
{ "_id" : "hdshard2", "host" : "hdshard2/172.16.254.136:40002,172.16.254.137:40002,172.16.254.138:40002", "state" : 1 }
{ "_id" : "hdshard3", "host" : "hdshard3/172.16.254.136:40003,172.16.254.137:40003,172.16.254.138:40003", "state" : 1 }

查看所有数据库分片情况

mongos> use config
switched to db config
mongos> db.databases.find() 
{ "_id" : "db5", "primary" : "hdshard2", "partitioned" : true, "version" : { "uuid" : UUID("bc5d26af-5248-431b-8065-7143fdbffb97"), "lastMod" : 1 } }
{ "_id" : "db6", "primary" : "hdshard3", "partitioned" : false, "version" : { "uuid" : UUID("6a1dd60f-a1fc-47be-9fad-d8ce01841d68"), "lastMod" : 1 } }
{ "_id" : "recommend", "primary" : "hdshard1", "partitioned" : false, "version" : { "uuid" : UUID("cb833b8e-cc4f-4c52-83c3-719aa383bac4"), "lastMod" : 1 } }

可以看到db5开启了分片，db6和recommend没有开启分片。

激活数据库分片功能

mongos> sh.enableSharding("db6")
{
    "ok" : 1,
    "operationTime" : Timestamp(1618480521, 3),
    "$clusterTime" : {
        "clusterTime" : Timestamp(1618480521, 3),
        "signature" : {
            "hash" : BinData(0,"ReiWhtUTkbTud9SM+7N2+WyhBcs="),
            "keyId" : NumberLong("6941260985399246879")
        }
    }
}
mongos> 
mongos> sh.enableSharding("recommend")
{
    "ok" : 1,
    "operationTime" : Timestamp(1618480562, 4),
    "$clusterTime" : {
        "clusterTime" : Timestamp(1618480562, 4),
        "signature" : {
            "hash" : BinData(0,"NJG21ltpt/C7h5SH7CKvnT95I+k="),
            "keyId" : NumberLong("6941260985399246879")
        }
    }
}

验证数据库分片情况

mongos> db.databases.find()
{ "_id" : "db5", "primary" : "hdshard2", "partitioned" : true, "version" : { "uuid" : UUID("bc5d26af-5248-431b-8065-7143fdbffb97"), "lastMod" : 1 } }
{ "_id" : "db6", "primary" : "hdshard3", "partitioned" : true, "version" : { "uuid" : UUID("6a1dd60f-a1fc-47be-9fad-d8ce01841d68"), "lastMod" : 1 } }
{ "_id" : "recommend", "primary" : "hdshard1", "partitioned" : true, "version" : { "uuid" : UUID("cb833b8e-cc4f-4c52-83c3-719aa383bac4"), "lastMod" : 1 } }

可以看到db6和recommend库都已活数据库分片。

判断是否为分片集群

mongos> db.runCommand({ isdbgrid : 1})
{
    "isdbgrid" : 1,
    "hostname" : "mongo7",
    "ok" : 1,
    "operationTime" : Timestamp(1618486042, 13),
    "$clusterTime" : {
        "clusterTime" : Timestamp(1618486042, 13),
        "signature" : {
            "hash" : BinData(0,"3k9SyHGJqe/nbacFkPTxo59smNA="),
            "keyId" : NumberLong("6941260985399246879")
        }
    }
}

列出开启分片的数据库

mongos> use config
switched to db config
mongos> db.databases.find( { "partitioned": true } )
{ "_id" : "db5", "primary" : "hdshard2", "partitioned" : true, "version" : { "uuid" : UUID("bc5d26af-5248-431b-8065-7143fdbffb97"), "lastMod" : 1 } }
{ "_id" : "db6", "primary" : "hdshard3", "partitioned" : true, "version" : { "uuid" : UUID("6a1dd60f-a1fc-47be-9fad-d8ce01841d68"), "lastMod" : 1 } }
{ "_id" : "recommend", "primary" : "hdshard1", "partitioned" : true, "version" : { "uuid" : UUID("cb833b8e-cc4f-4c52-83c3-719aa383bac4"), "lastMod" : 1 } }

查看分片键

mongos> db.collections.find()
{ "_id" : "config.system.sessions", "lastmodEpoch" : ObjectId("60547131a531190b111e42a0"), "lastmod" : ISODate("1970-02-19T17:02:47.296Z"), "dropped" : false, "key" : { "_id" : 1 }, "unique" : false, "uuid" : UUID("f8a8e664-10d2-41fb-84ec-a165579ee86d") }
{ "_id" : "db5.db5", "lastmodEpoch" : ObjectId("6054804d6410651de69524d9"), "lastmod" : ISODate("1970-02-19T17:02:47.296Z"), "dropped" : false, "key" : { "id" : 1 }, "unique" : false, "uuid" : UUID("2122da21-7279-4b88-b60f-73dd3d0276fb") }