mongodb - 识别 mongo 集群的陈旧成员

如果 mongo 节点离线时间过长，并且 oplog 在它恢复之前包装，那么它可能会陷入陈旧状态并需要手动干预。如何从副本集状态文档中识别该状态？它是否会停留在状态 3，它也被处于维护模式的节点使用，并且可能被可以 catch 的节点使用？如果是这样，我如何区分？

来自 http://docs.mongodb.org/manual/reference/replica-status/ :

Number State
0      Starting up, phase 1 (parsing configuration)
1      Primary
2      Secondary
3      Recovering (initial syncing, post-rollback, stale members)
4      Fatal error
5      Starting up, phase 2 (forking threads)
6      Unknown state (the set has never connected to the member)
7      Arbiter
8      Down
9      Rollback
10     Removed

最佳答案

它将处于状态 3，正在恢复。要专门识别陈旧状态，您需要查找 errmsg 字段。当陈旧时，有问题的辅助将有一个这样的 errmsg:

"errmsg" : "error RS102 too stale to catch up"

就完整输出而言，它看起来像这样:

 rs.status()
{
        "set" : "testReplSet",
        "date" : ISODate("2013-01-29T01:39:38Z"),
        "myState" : 1,
        "members" : [
                {
                        "_id" : 0,
                        "name" : "hostname:31000",
                        "health" : 1,
                        "state" : 1,
                        "stateStr" : "PRIMARY",
                        "uptime" : 507,
                        "optime" : Timestamp(1359423456000, 893),
                        "optimeDate" : ISODate("2013-01-29T01:37:36Z"),
                        "self" : true
                },
                {
                        "_id" : 1,
                        "name" : "hostname:31001",
                        "health" : 1,
                        "state" : 2,
                        "stateStr" : "SECONDARY",
                        "uptime" : 483,
                        "optime" : Timestamp(1359423456000, 893),
                        "optimeDate" : ISODate("2013-01-29T01:37:36Z"),
                        "lastHeartbeat" : ISODate("2013-01-29T01:39:37Z"),
                        "pingMs" : 0
                },
                {
                        "_id" : 2,
                        "name" : "hostname:31002",
                        "health" : 1,
                        "state" : 3,
                        "stateStr" : "RECOVERING",
                        "uptime" : 4,
                        "optime" : Timestamp(1359423087000, 1),
                        "optimeDate" : ISODate("2013-01-29T01:31:27Z"),
                        "lastHeartbeat" : ISODate("2013-01-29T01:39:38Z"),
                        "pingMs" : 0,
                        "errmsg" : "error RS102 too stale to catch up"
                }
        ],
        "ok" : 1
}

最后，一个代码片段仅用于从 shell 打印错误(如果存在):

rs.status().members.forEach(function printError(rsmember){if (rsmember.errmsg){print(rsmember.errmsg)}})

关于mongodb - 识别 mongo 集群的陈旧成员，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/14573763/