[SERVER-12010] Mongos process not starting if more than 3 config servers in the process arguments Created: 09/Dec/13  Updated: 10/Dec/14  Resolved: 12/Dec/13

Status: Closed
Project: Core Server
Component/s: Sharding
Affects Version/s: 2.4.6
Fix Version/s: None

Type: Bug Priority: Major - P3
Reporter: Krishnachaitanya Thummuru Assignee: Unassigned
Resolution: Done Votes: 0
Labels: sharding
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified
Environment:

Linux CentOs 5.7/5.8


Operating System: Linux
Participants:

 Description   

Hi,

For more redundancy i had created 5 config server process in 5 different machines, and added the 5 config server information in mongos process.
When i try to start mongos process, mongos process is failed to start with the below error

Mongos server process:

  1. mongos --configdb host01:47720,host2:47720,host3:47720,host4:47720,host5:47720 --pidfilepath /var/run/mongos-57720.pid --port 57720 --fork --logpath /var/log/mongos-57720.log --logappend --quiet
    Mon Dec 9 07:15:55.921 need either 1 or 3 configdbs
    #

I did not find any error or any other logs updated in the mongos logs, straight away it's though "need either 1 or 3 configdbs" message on screen and exit.

Config servers active and running
On host 1
root 30859 1 0 07:12 ? 00:00:00 /usr/bin/mongod --configsvr --port 47720 --smallfiles --dbpath=/data/configSrv-47720 --fork --logpath /var/log/configServer-47720.log --logappend --quiet

On host2
root 8371 1 0 07:08 ? 00:00:00 /usr/bin/mongod --configsvr --port 47720 --smallfiles --dbpath=/data/configSrv-47720 --fork --logpath /var/log/configServer-47720.log --logappend --quiet

On host3
root 9428 1 0 07:12 ? 00:00:00 /usr/bin/mongod --configsvr --port 47720 --smallfiles --dbpath=/data/configSrv-47720 --fork --logpath /var/log/configServer-47720.log --logappend --quiet

On host4
root 14085 1 0 07:12 ? 00:00:00 /usr/bin/mongod --configsvr --port 47720 --smallfiles --dbpath=/data/configSrv-47720 --fork --logpath /var/log/configServer-47720.log --logappend --quiet

on host5
root 18046 1 0 07:12 ? 00:00:00 /usr/bin/mongod --configsvr --port 47720 --smallfiles --dbpath=/data/configSrv-47720 --fork --logpath /var/log/configServer-47720.log --logappend --quiet

I am not sure why mongos process is not starting, mongos process will it allow maximum three config servers only?

Could you please let me know why its not allowing to add more than 3 configdbs?

Thanks & Regards
Krishnachaitanya



 Comments   
Comment by Asya Kamsky [ 12/Dec/13 ]

Hi,

You can read about how to deploy a sharded cluster in our docs:

http://docs.mongodb.org/manual/tutorial/deploy-shard-cluster/

Asya

Comment by Krishnachaitanya Thummuru [ 12/Dec/13 ]

Hi Eliot

Thanks for your update!
Could you please let me know where can i get the information about the supporting of the config servers by a mongo cluster, It would be helpful if you share any document or link.

Thanks & Regards
Krishnachaitanya

Comment by Eliot Horowitz (Inactive) [ 12/Dec/13 ]

A mongo cluster needs exactly three config servers.
5 is not supported.

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