Comment 53 for bug 607560

I has this problem as well. I was able to resolve the problem (or at lease significantly reduce the issue of jbd2 writes as reported in iotop) by mounting my /tmp, /var/tmp, and my /var/log into a tmpfs in fstab. I believe /var/log is the culprit. After mounting var/log (although it is possible it is /tmp or /var/tmp - I didn't test each individually) to tmpfs at boot (via fstab), the problem goes away. I assume the "writes" are still occurring, but are being written to RAM rather than to disk.

If the above is true, the problem is likely related to logging. I would be interested to hear someone else trying the above "solution" to see if the problem is resolved.

example lines from my fstab:

tmp /tmp tmpfs rw,nosuid,nodev,noexec,noatime,mode=1777,size=1024k 0 0
vartmp /var/tmp tmpfs rw,nosuid,nodev,noexec,noatime,mode=1777,size=1024k 0 0
varlog /var/log tmpfs rw,nosuid,nodev,noexec,noatime,mode=0755,size=8192k 0 0