The oplog exists internally as a capped collection, so you cannot modify its size in the course of normal operations.另：改變oplog大小，需要在每個節(jié)點上執(zhí)行維護模式。（官方推薦）

1.關(guān)閉mongod

關(guān)閉mongod實例，如果是primary節(jié)點，執(zhí)行rs.stepDown() 降級

handong1:PRIMARY> rs.stepDown()
{
	"ok" : 1,
	"$clusterTime" : {
		"clusterTime" : Timestamp(1619693040, 1),
		"signature" : {
			"hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
			"keyId" : NumberLong(0)
		}
	},
	"operationTime" : Timestamp(1619693040, 1)
}
handong1:SECONDARY> 
handong1:SECONDARY> 
handong1:SECONDARY> 
handong1:SECONDARY> use admin
switched to db admin
handong1:SECONDARY> db.shutdownServer()
2021-04-29T18:44:33.947+0800 I  NETWORK  [js] DBClientConnection failed to receive message from 127.0.0.1:27017 - HostUnreachable: Connection closed by peer
server should be down...
2021-04-29T18:44:33.950+0800 I  NETWORK  [js] trying reconnect to 127.0.0.1:27017 failed
2021-04-29T18:44:33.967+0800 I  NETWORK  [js] reconnect 127.0.0.1:27017 failed failed

2.修改配置文件

修改配置文件，修改端口，注釋掉replSet和認證相關(guān)的設(shè)置

port=27018
fork=true
journal = true
maxConns=500
logappend=true
directoryperdb=true
dbpath=/mongodb/data
logpath=/mongodb/logs/mongodb.log

3.啟動mongod實例，并備份oplog

mongod -f /mongodb/conf/mongodb.conf 
about to fork child process, waiting until server is ready for connections.
forked process: 31553
child process started successfully, parent exiting

mongodump -d local -c oplog.rs --port 27018 -h 172.16.254.134 -o /mongodb/backup
2021-04-29T18:55:18.167+0800	writing local.oplog.rs to /mongodb/backup/local/oplog.rs.bson
2021-04-29T18:55:18.170+0800	done dumping local.oplog.rs (798 documents)

4.重建oplog

保存oplog最新時間點

> use local
switched to db local
> db.temp.save( db.oplog.rs.find( { }, { ts: 1, h: 1 } ).sort( {$natural : -1} ).limit(1).next() )
WriteResult({ "nInserted" : 1 })

> db.temp.find()
{ "_id" : ObjectId("608a914089abaa981f14e888"), "ts" : Timestamp(1619693066, 1), "h" : NumberLong(0) }

刪除舊的oplog

db.oplog.rs.drop()

重建新的oplog，大小為2GB

> db.runCommand( { create: "oplog.rs", capped: true, size: (2 * 1024 * 1024 * 1024) } )

5.插入前面保存的oplog時間點記錄

> db.oplog.rs.save( db.temp.findOne() )
> db.oplog.rs.find()

6.關(guān)閉mongod實例

> use admin
switched to db admin
> db.shutdownServer()
2021-04-29T19:06:53.745+0800 I  NETWORK  [js] DBClientConnection failed to receive message from 127.0.0.1:27018 - HostUnreachable: Connection closed by peer
server should be down...
2021-04-29T19:06:53.749+0800 I  NETWORK  [js] trying reconnect to 127.0.0.1:27018 failed
2021-04-29T19:06:53.749+0800 I  NETWORK  [js] reconnect 127.0.0.1:27018 failed failed

最后恢復(fù)mongodb.conf到初始狀態(tài)，啟動

方法四

如果你的MongoDB版本為4.0以后的版本，可以直接使用replSetResizeOplog修改。

1.查看oplog大小

handong1:SECONDARY> db.getReplicationInfo()
{
	"logSizeMB" : 1000,
	"usedMB" : 0.17,
	"timeDiff" : 6736,
	"timeDiffHours" : 1.87,
	"tFirst" : "Thu Apr 29 2021 17:19:14 GMT+0800 (CST)",
	"tLast" : "Thu Apr 29 2021 19:11:30 GMT+0800 (CST)",
	"now" : "Thu Apr 29 2021 19:11:42 GMT+0800 (CST)"
}

2.修改oplog大小

handong1:SECONDARY> db.adminCommand({replSetResizeOplog:1,size:2000})
{
	"ok" : 1,
	"$clusterTime" : {
		"clusterTime" : Timestamp(1619694744, 14),
		"signature" : {
			"hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
			"keyId" : NumberLong(0)
		}
	},
	"operationTime" : Timestamp(1619694744, 14)
}

3.驗證oplog大小

handong1:SECONDARY> db.getReplicationInfo()
{
	"logSizeMB" : 2000,
	"usedMB" : 0.18,
	"timeDiff" : 6852,
	"timeDiffHours" : 1.9,
	"tFirst" : "Thu Apr 29 2021 17:19:14 GMT+0800 (CST)",
	"tLast" : "Thu Apr 29 2021 19:13:26 GMT+0800 (CST)",
	"now" : "Thu Apr 29 2021 19:13:28 GMT+0800 (CST)"
}

4.整理碎片，回收空間（可選）

handong1:SECONDARY> use local
switched to db local
handong1:SECONDARY> db.runCommand({"compact" : "oplog.rs"})
{
	"ok" : 1,
	"$clusterTime" : {
		"clusterTime" : Timestamp(1619694840, 1),
		"signature" : {
			"hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
			"keyId" : NumberLong(0)
		}
	},
	"operationTime" : Timestamp(1619694840, 1)
}

到此這篇關(guān)于分享MongoDB修改oplog大小的4種方法的文章就介紹到這了,更多相關(guān)MongoDB修改oplog大小內(nèi)容請搜索腳本之家以前的文章或繼續(xù)瀏覽下面的相關(guān)文章希望大家以后多多支持腳本之家！

您可能感興趣的文章: