Thread (11 messages) 11 messages, 4 authors, 2012-02-15

Re: quotacheck speed

From: Arkadiusz Miśkiewicz <hidden>
Date: 2012-02-14 05:35:51

On Tuesday 14 of February 2012, Dave Chinner wrote:
On Mon, Feb 13, 2012 at 07:09:50PM +0100, Arkadiusz Miśkiewicz wrote:
quoted
On Monday 13 of February 2012, Christoph Hellwig wrote:
quoted
On Sun, Feb 12, 2012 at 10:01:07PM +0100, Arkadiusz Mi??kiewicz wrote:
quoted
Hi,

When mounting 800GB filesystem (after repair for example) here
quotacheck takes 10 minutes. Quite long time that adds to whole time
of filesystem downtime (repair + quotacheck).

I wonder if quotacheck can be somehow improved or done differently
like doing it in parallel with normal fs usage (so there will be no
downtime) ?
I think the best idea to improve the performance in case you did a
repair is to integrate the quotacheck code into repair.  It's fairly
simple given that quotacheck simply walks all inodes and adds their
space usage to the correct user/group/project, and given that repair
already walks all inodes, and checks their block maps it does most of
that work already.
That would be interesting and probably make
quoted
The only downside would be that the memory usage
of repair increases a bit by keeping the dquots in memoryb, but even
for your 130000 dquot setup that would add about 100 bytes * 130000
please a bit of in-memory metadata (less than 20MB total) of memory
usage, so it probably is a good tradeoff.


In what cases do you regularly run quotacheck when you did not do
a repair first?
I don't initiate quotacheck manually. AFAIK internal xfs quotacheck
happens in two cases here:
1) repair->mount
2) filesystem has quotacheck done properly some time ago -> umount ->
mount-
quoted
oops/reset/something like that happens while mounting -> new mount
So you'd like both quotacheck to be sped up and repair
to do it as well? ;)
Well, 1) is happening much more often than 2) :-)

-- 
Arkadiusz Miśkiewicz        PLD/Linux Team
arekm / maven.pl            http://ftp.pld-linux.org/

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