[原创] MongoDB管理与开发精要《红丸出品》21.2 复制集之主从操作日志oplog
http://blog.chinaunix.net/attachment/201205/26/26785103_1338009683Kvjx.jpg21.2主从操作日志oplogMongoDB的Replica Set架构是通过一个日志来存储写操作的，这个日志就叫做”oplog”。 oplog.rs 是一个固定长度的 capped collection，它存在于”local”数据库中，用于记录 Replica Sets 操作日志。在默认情况下,对于64位的MongoDB,oplog是比较大的，可以达到5%的磁盘空间。oplog的大小是可以通过mongod的参数”—oplogSize”来改变oplog的日志大小。Oplog内容样例:
rs1:PRIMARY> use localswitched to db localrs1:PRIMARY> show collectionsoplog.rssystem.replsetrs1:PRIMARY> db.oplog.rs.find(){ "ts" : { "t" : 1338457763000, "i" : 1 }, "h" : NumberLong(0), "op" : "n", "ns" : "", "o" : { "msg" : "initiating set" } }{ "ts" : { "t" : 1338459114000, "i" : 1 }, "h" : NumberLong("5493127699725549585"), "op" : "i", "ns" : "test.c1", "o" : { "_id" : ObjectId("4fc743e9aea289af709ac6b5"), "age" : 29, "name" : "Tony" } }rs1:PRIMARY>
字段说明:lts: 某个操作的时间戳lop: 操作类型，如下：ui: insertud: deleteuu: updatelns: 命名空间，也就是操作的collectionnamelo: document的内容
查看master的oplog元数据信息：
rs1:PRIMARY> db.printReplicationInfo()configured oplog size: 47.6837158203125MBlog length start to end: 1351secs (0.38hrs)oplog first event time:Thu May 31 2012 17:49:23 GMT+0800 (CST)oplog last event time: Thu May 31 2012 18:11:54 GMT+0800 (CST)now: Thu May 31 2012 18:21:58 GMT+0800 (CST)rs1:PRIMARY>
字段说明:lconfigured oplog size: 配置的oplog文件大小llog length start to end: oplog日志的启用时间段loplog first event time: 第一个事务日志的产生时间loplog last event time: 最后一个事务日志的产生时间lnow: 现在的时间
查看slave的同步状态：
rs1:PRIMARY> db.printSlaveReplicationInfo()source: localhost:28011 syncedTo: Thu May 31 2012 18:11:54 GMT+0800 (CST) = 884secs ago (0.25hrs)source: localhost:28012 syncedTo: Thu May 31 2012 18:11:54 GMT+0800 (CST) = 884secs ago (0.25hrs)rs1:PRIMARY>
字段说明:lsource: 从库的IP及端口lsyncedTo: 目前的同步情况，延迟了多久等信息免费IT培训（ChinaDBA.net）实践者！学费1元，全捐公益
http://service.t.sina.com.cn/widget/qmd/2446082491/9e768382/1.png
页:
[1]