MongoDB Master-Slaver模式主备切换问题

[404你懂得]

下面是官网上关于 Master-Slaver模式主备切换步骤
1、 Halt writes on A using the fsync command.
2、Make sure B is up to date with the state of A.
3、 Shut down B.
4、Back up and move all data files that begin with local on B from the dbPath to remove the existing local.sources data.
Warning
Removing local.* is irrevocable and cannot be undone. Perform this step with extreme caution.
5、Start B with the --master option.
6、Do a write on B, which primes the oplog to provide a new sync start point.
7、Shut down B. B will now have a new set of data files that start with local.
8、Shut down A and replace all files in the dbPath of A that start with local with a copy of the files in the dbPath of B that begin with local.
9、Considering compressing the local files from B while you copy them, as they may be quite large.
10、Start B with the --master option.
11、Start A with all the usual slave options, but include fastsync.

关于第三步我不很明白，删除local.source data,这个local.sources data是哪个文件

[rucypli]

Master-Slaver你可以理解为已经废弃了

[rucypli]

应该搭建replicat set 翻译过来是 副本集模式

[404你懂得]

目前只有两台主机，需要搭建热备，故只能使用master-slave模式，local.sources可以通过use local;db.sources.stats().wiredTiger.uri来查找到，但是我移除了这个文件，mongoDB无法启动，报WiredTiger error (2) [1520299616:34915][30051:0x7f2831ba2d80], file:local/collection-0--2786426632940137551.wt, WT_SESSION.open_cursor: /var/lib/mongodb/data/db/local/collection-0--2786426632940137551.wt: handle-open: open: No such file or directory

[rucypli]

两台也可以 仲裁放到其中一台上端口不一致即可（虽然这样不推荐）

[404你懂得]

replicat set 需要3台主机，主，备，仲裁，目前有个环境只有两台主机，无法搭建replicat set

[404你懂得]

这样不是无法保证热备正常了，如果主和仲裁在同一台主机上，这台主机挂了，备也无法接管服务，master-slave虽然也无法自动切换，但是可以通过自定义脚本来切换

[rucypli]

可以把仲裁节点放在一个web机器上，仅仅是一个进程而已