From: Calvin Morrow <calvin.morrow@gmail.com>
To: Tommi Virtanen <tv@inktank.com>
Cc: Vladimir Bashkirtsev <vladimir@bashkirtsev.com>,
Josh Durgin <josh.durgin@inktank.com>,
ceph-devel@vger.kernel.org
Subject: Re: Poor read performance in KVM
Date: Thu, 19 Jul 2012 12:06:17 -0600 [thread overview]
Message-ID: <CADxhoDT8rimSwP+Y75tGVo3Nd5WYw8xHyDxBAMV8tb5no0OP4Q@mail.gmail.com> (raw)
In-Reply-To: <CADvuQRGaivtgho4R=rk3c_B6eJ2GfG=tZFGNy9knoKyh2CR-zg@mail.gmail.com>
On Thu, Jul 19, 2012 at 9:52 AM, Tommi Virtanen <tv@inktank.com> wrote:
>
> On Thu, Jul 19, 2012 at 5:19 AM, Vladimir Bashkirtsev
> <vladimir@bashkirtsev.com> wrote:
> > Look like that osd.0 performs with low latency but osd.1 latency is way
> > too
> > high and on average it appears as 200ms. osd is backed by btrfs over
> > LVM2.
> > May be issue lie in backing fs selection? All four osds running similar
>
> Our typical experience with btrfs right now seems to be that it works
> fast when the filesystem is fresh, but as it ages, it starts to have
> higher and higher delays on syncing writes. This does not seem to be
> completely deterministic, that is, if you run many btrfs'es, the
> symptoms start to appear at different times on different instances.
Is Inktank seeing the slowdown on btrfs volumes with large metadata
(32k / 64k) node/leaf sizes as well, or only on default (4k) sizes?
Vladmir,
What node/leaf size are you using on your btrfs volume?
> --
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next prev parent reply other threads:[~2012-07-19 18:06 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-15 13:13 Poor read performance in KVM Vladimir Bashkirtsev
2012-07-16 6:16 ` Josh Durgin
2012-07-18 5:46 ` Vladimir Bashkirtsev
2012-07-18 15:27 ` Josh Durgin
2012-07-19 10:46 ` Vladimir Bashkirtsev
2012-07-19 12:19 ` Vladimir Bashkirtsev
2012-07-19 15:52 ` Tommi Virtanen
2012-07-19 18:06 ` Calvin Morrow [this message]
2012-07-19 18:15 ` Mark Nelson
2012-07-20 5:24 ` Vladimir Bashkirtsev
2012-07-20 5:24 ` Vladimir Bashkirtsev
2012-07-20 5:20 ` Vladimir Bashkirtsev
[not found] ` <50080D9D.8010306@bashkirtsev.com>
2012-07-19 18:42 ` Josh Durgin
2012-07-20 5:31 ` Vladimir Bashkirtsev
2012-07-20 16:17 ` Vladimir Bashkirtsev
2012-07-20 16:42 ` Tommi Virtanen
2012-07-20 16:53 ` Mark Nelson
2012-07-20 16:53 ` Vladimir Bashkirtsev
2012-07-29 15:31 ` Vladimir Bashkirtsev
2012-07-29 16:13 ` Mark Nelson
2012-07-18 15:34 ` Josh Durgin
2012-07-18 5:49 ` Vladimir Bashkirtsev
2012-07-18 5:51 ` Vladimir Bashkirtsev
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