[SERVER-8373] mongod is checking the other shard's replica set with ReplicaSetMonitorWatcher Created: 29/Jan/13  Updated: 15/Feb/13  Resolved: 29/Jan/13

Status: Closed
Project: Core Server
Component/s: Logging
Affects Version/s: 2.2.2
Fix Version/s: None

Type: Question Priority: Major - P3
Reporter: Anton V. Volokhov Assignee: Unassigned
Resolution: Done Votes: 0
Labels: replicaset, sharding
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified
Environment:

ubuntu 12.04


Participants:

 Description   

2 shards, each one is a replica set with 3 machines.
shards are named shard1 and shard2
shard1 consists of cs-mongodb01

{d|g|f} machines,
shard2 consists of cs-mongodb02{d|g|f}

machines.

there are plenty of following logs on shard2 machines:
Tue Jan 29 07:15:54 [ReplicaSetMonitorWatcher] dbclient_rs nodes[2].ok = true cs-mongodb01g.load.net:27017
Tue Jan 29 07:15:54 [ReplicaSetMonitorWatcher] dbclient_rs nodes[0].ok = true cs-mongodb01d.load.net:27017
Tue Jan 29 07:15:54 [ReplicaSetMonitorWatcher] dbclient_rs nodes[1].ok = true cs-mongodb01f.load.net:27017
Tue Jan 29 07:16:04 [ReplicaSetMonitorWatcher] checking replica set: shard1
Tue Jan 29 07:16:04 [ReplicaSetMonitorWatcher] ReplicaSetMonitor::_checkConnection: cs-mongodb01g.load.net:27017

{ setName: "shard1", ismaster: true, secondary: false, hosts: [ "cs-mongodb01g.load.net:27017", "cs-mongodb01f.load.net:27017", "cs-mongodb01d.load.net:27017" ], primary: "cs-mongodb01g.load.net:27017", me: "cs-mongodb01g.load.net:27017", maxBsonObjectSize: 16777216, localTime: new Date(1359429364931), ok: 1.0 }

Tue Jan 29 07:16:04 [ReplicaSetMonitorWatcher] dbclient_rs nodes[2].ok = true cs-mongodb01g.load.net:27017
Tue Jan 29 07:16:04 [ReplicaSetMonitorWatcher] dbclient_rs nodes[0].ok = true cs-mongodb01d.load.net:27017
Tue Jan 29 07:16:04 [ReplicaSetMonitorWatcher] dbclient_rs nodes[1].ok = true cs-mongodb01f.load.net:27017
Tue Jan 29 07:16:04 [ReplicaSetMonitorWatcher] _check : shard1/cs-mongodb01d.load.net:27017,cs-mongodb01f.load.net:27017,cs-mongodb01g.load.net:27017
Tue Jan 29 07:16:04 [ReplicaSetMonitorWatcher] ReplicaSetMonitor::_checkConnection: cs-mongodb01d.load.net:27017

{ setName: "shard1", ismaster: false, secondary: true, hosts: [ "cs-mongodb01d.load.net:27017", "cs-mongodb01f.load.net:27017", "cs-mongodb01g.load.net:27017" ], primary: "cs-mongodb01g.load.net:27017", me: "cs-mongodb01d.load.net:27017", maxBsonObjectSize: 16777216, localTime: new Date(1359429364932), ok: 1.0 }

Tue Jan 29 07:16:04 [ReplicaSetMonitorWatcher] dbclient_rs nodes[2].ok = true cs-mongodb01g.load.net:27017
Tue Jan 29 07:16:04 [ReplicaSetMonitorWatcher] dbclient_rs nodes[0].ok = true cs-mongodb01d.load.net:27017
Tue Jan 29 07:16:04 [ReplicaSetMonitorWatcher] dbclient_rs nodes[1].ok = true cs-mongodb01f.load.net:27017
Tue Jan 29 07:16:04 [ReplicaSetMonitorWatcher] ReplicaSetMonitor::_checkConnection: cs-mongodb01g.load.net:27017

{ setName: "shard1", ismaster: true, secondary: false, hosts: [ "cs-mongodb01g.load.net:27017", "cs-mongodb01f.load.net:27017", "cs-mongodb01d.load.net:27017" ], primary: "cs-mongodb01g.load.net:27017", me: "cs-mongodb01g.load.net:27017", maxBsonObjectSize: 16777216, localTime: new Date(1359429364934), ok: 1.0 }

Tue Jan 29 07:16:04 [ReplicaSetMonitorWatcher] dbclient_rs nodes[2].ok = true cs-mongodb01g.load.net:27017
Tue Jan 29 07:16:04 [ReplicaSetMonitorWatcher] dbclient_rs nodes[0].ok = true cs-mongodb01d.load.net:27017
Tue Jan 29 07:16:04 [ReplicaSetMonitorWatcher] dbclient_rs nodes[1].ok = true cs-mongodb01f.load.net:27017
Tue Jan 29 07:16:04 [ReplicaSetMonitorWatcher] ReplicaSetMonitor::_checkConnection: cs-mongodb01f.load.net:27017

{ setName: "shard1", ismaster: false, secondary: true, hosts: [ "cs-mongodb01f.load.net:27017", "cs-mongodb01d.load.net:27017", "cs-mongodb01g.load.net:27017" ], primary: "cs-mongodb01g.load.net:27017", me: "cs-mongodb01f.load.net:27017", maxBsonObjectSize: 16777216, localTime: new Date(1359429364935), ok: 1.0 }

Tue Jan 29 07:16:04 [ReplicaSetMonitorWatcher] dbclient_rs nodes[2].ok = true cs-mongodb01g.load.net:27017
Tue Jan 29 07:16:04 [ReplicaSetMonitorWatcher] dbclient_rs nodes[0].ok = true cs-mongodb01d.load.net:27017
Tue Jan 29 07:16:04 [ReplicaSetMonitorWatcher] dbclient_rs nodes[1].ok = true cs-mongodb01f.load.net:27017
Tue Jan 29 07:16:04 [ReplicaSetMonitorWatcher] ReplicaSetMonitor::_checkConnection: cs-mongodb01g.load.net:27017

{ setName: "shard1", ismaster: true, secondary: false, hosts: [ "cs-mongodb01g.load.net:27017", "cs-mongodb01f.load.net:27017", "cs-mongodb01d.load.net:27017" ], primary: "cs-mongodb01g.load.net:27017", me: "cs-mongodb01g.load.net:27017", maxBsonObjectSize: 16777216, localTime: new Date(1359429364968), ok: 1.0 }

Tue Jan 29 07:16:04 [ReplicaSetMonitorWatcher] dbclient_rs nodes[2].ok = true cs-mongodb01g.load.net:27017
Tue Jan 29 07:16:04 [ReplicaSetMonitorWatcher] dbclient_rs nodes[0].ok = true cs-mongodb01d.load.net:27017
Tue Jan 29 07:16:04 [ReplicaSetMonitorWatcher] dbclient_rs nodes[1].ok = true cs-mongodb01f.load.net:27017

Why mongod is trying to check another replica's instances? Is it ok?
I thought, that information about shards is stored only on config servers, and mongod instances knows nothing about them.



 Comments   
Comment by Scott Hernandez (Inactive) [ 29/Jan/13 ]

Please ask questions like this on google groups (https://groups.google.com/group/mongodb-user). The server project is filing feature requests and bugs.

This is expected behavior as shards need to communicate and monitor each other for chunk migration operations. The knowledge about the cluster members/shards does come from the config database but is cached and maintained in the running instances.

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