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Jbd2 forces frequent hard-drive wake-ups

June 6th, 2012 2 comments

System: Debian GNU/Linux (wheezy) 3.2.0-2-amd64

Some time ago I realized frequent spinup-spindowns of the hard drive of my laptop. Not only this is annoying, it also kills power-management.

After a little investigation using iotop, I found jbd2-service having write-access to the disk every few seconds. According to this thread: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/607560 jbd2 flushes ext4 journal to disk. This is a necessary evil, but the interval between two flushes can be increased by adding ‘commit=$N‘, where $N is the amount of time in seconds, to all regarding options columns in /etc/fstab.

Example:

...
UUID=820b416a-993f-4fe9-8191-a9453efaa923    /    ext4    errors=remount-ro,commit=180    0    1
...

The interval should not be to large to prevent massive data loss on failures. I decided to choose 3 minutes here. Don’t forget to remount/reboot! By now all works fine 🙂

Categories: linux Tags: , , ,