Question :
When one of masters is unreachable all other replica sets work too slow in mongodb 2.6.11, also I can not list the databases on mongos servers, and that is because of one replica set. How to solve this problem.
Update:
I have found this https://jira.mongodb.org/browse/SERVER-7246, do they say “If you have no redundant network connection to remote site, then go to hell”?
Answer :
Replica sets are individual entities unless you are sharing resources among them like CPU,RAM,Disk… running multiple mongods in a single server.
I believe your case is that on a sharded cluster scatter-gather queries speed is determined by the slowest shard, so when one shard gets slow all scatter-gather queries will turn slow.
Upgrading to 3.0.7 and switching to wiredtiger solved this issue.