Mongodb starts slowly: [initandlisten] fo

Fault phenomenon

After mongodb starts, it waits for dozens of minutes to complete, and the single node replica set is in startup all the time.

Cause analysis:

Check the error log of mongod and find: [initandlisten] found 1 index (es) that wasn't finished before shutdown.

According to the message in the error log, the reason seems to be like this: before db shuts down, one or two large index building operations are not completed, db will directly shutdown, and when db starts again, mongo will rebuild the index by default and be in the startup state during reconstruction.

Treatment method

Since it is not clear how long building index will last, according to the error log prompt, restart mongod with the-- noIndexBuildRetry parameter to skip index reconstruction. After the startup is complete, evaluate whether the index needs to be established.