[Bug 131094] Re: Heavy Disk I/O harms desktop responsiveness

Paulo J. S. Silva pjssilva at ime.usp.br
Fri May 1 14:55:08 UTC 2009

In my machine I found a workaround after reading many threads in the
subject. If you are using ext3, try changing the data mode. The ext3
filesystem has three modes. The default one is "ordered", the other two
are "writeback" and "journal". They differ basically by the amount of
information that is written to the journal before the real write to
disk, the more information better the recovery from a system crash. The
safest mode is journal, followed by ordered and then writeback.

In my machine, if I change the mode from ordered to journal or writeback
the slowness under heavy load becomes much more bearable (it is not
completely gone, but acceptable). In my case journal mode is the best,
even though it is supposed to be the slowest mode (but the safest). I
can now use tracker again.

To change the mode of your disk partitions (you need to do it for each
partition) use tune2fs. For example

sudo tune2fs -o journal_data /dev/sda6

changes  the mode to journal in partition sda6. To change the mode to
writeback try

sudo tune2fs -o journal_data_writeback /dev/sda6

and to ordered (the default in Ubuntu)

sudo tune2fs -o journal_data_ordered /dev/sda6

After using tune2fs you need to reboot.

Obs: It seems that writeback may become the default mode in future
kernels (or maybe they will use a new mode called guarded). The new
kernels are supposed to have lots of fixes in this issue.

Heavy Disk I/O harms desktop responsiveness
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