Hello,I am a user from China. I'm sorry my English is not good,but I will try my best to describe my problem clearly.

I have a cluster with 3 shards 3 config servers and 3 mongos.The dataset size is about 1T.I have may database and collections on this cluster.but almost all of the collectiosns is imbalance.The chunks moves very Slowly.

I check the logs,there are some problems:
【warning:config servers A and B differ】 this warning appears very often.
【ERROR: config servers not in sync !】
【when split chunk:the collection's metadata lock is taken】

I don't know what causes these problems occur.I hope to get help!
Thank you very much