Perhaps someone could tell me if this is expected or not (It doesn't seem normal to me)... On all 3 of my config servers I am seeing consistent high disk IO, even when the sharded-cluster has extremely low activity. According to iotop the mongodb process is causing disk writes fluctuating between about 500KB/s and 1000KB/s (there are virtually no reads). I know the log files are constantly being updated with sync messages (and would love to not have these logged), but looking at tail these are of the frequency of about 1 line per second on average, so I don't believe that this can account for the IO stats I see.
It was my understanding that config servers didn't really need to do that much, and mainly needed to keep track of how data is sharded (and since there are low db writes at the moment, there's not much of this going on). I'm running on Debian 6 64bit.
Can anyone tell me what might be happening here?