Btrfs devel - May 2013 - BTRFS in laptop-mode

Welcome,

What are perspectives on BTRFS complying with laptop-mode and stop 
writing to disk every 30 sec?

The thread was asked several years before 
(http://mailman.samwel.tk/pipermail/laptop-mode/2012-February/000520.html), 
but time went by and maybe the situation became a little more on the 
bright side...? With kernel 3.8.11 I can still see with lm-profiler a 
lot of "btrfs-transacti" and ""btrfs-submit-1" events,
roughly once
every 30 sec.

Is there any tunable switch, that can delay such writes to, say, 15 
minutes, or better yet: until the disk started spinning anyway?

-- 

Adam Ryczkowski
+48505919892 <callto:+48505919892>
Skype:sisteczko <skype:sisteczko>

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On Tue, May 14, 2013 at 10:32:43AM +0200, Adam Ryczkowski
wrote:
> What are perspectives on BTRFS complying with laptop-mode and stop writing
> to disk every 30 sec?
> Is there any tunable switch, that can delay such writes to, say, 15
minutes,
> or better yet: until the disk started spinning anyway?
30 seconds is the regular transaction commit interval. Tweaking the
value is easy (via a mount option to make it clearly visible):

http://lxr.free-electrons.com/source/fs/btrfs/disk-io.c#L1691

but has implications about data safety in case of a long delay in
combination with a crash.


david
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