From: Dave Chinner <dchinner@redhat.com>
To: David Casier <david.casier@aevoo.fr>
Cc: Ric Wheeler <rwheeler@redhat.com>, Sage Weil <sage@newdream.net>,
Ceph Development <ceph-devel@vger.kernel.org>,
Brian Foster <bfoster@redhat.com>,
Eric Sandeen <esandeen@redhat.com>
Subject: Re: Fwd: Fwd: [newstore (again)] how disable double write WAL
Date: Tue, 16 Feb 2016 14:35:38 +1100 [thread overview]
Message-ID: <20160216033538.GB2005@devil.localdomain> (raw)
In-Reply-To: <CA+gn+znGzF+J=qAk+511qdfPJV4xYB+4F5k8KMLWh0+JtryLeA@mail.gmail.com>
On Mon, Feb 15, 2016 at 04:18:28PM +0100, David Casier wrote:
> Hi Dave,
> 1TB is very wide for SSD.
It fills from the bottom, so you don't need 1TB to make it work
in a similar manner to the ext4 hack being described.
> Exemple with only 10GiB :
> https://www.aevoo.fr/2016/02/14/ceph-ext4-optimisation-for-filestore/
It's a nice toy, but it's not something that is going scale reliably
for production. That caveat at the end:
"With this model, filestore rearrange the tree very
frequently : + 40 I/O every 32 objects link/unlink."
Indicates how bad the IO patterns will be when modifying the
directory structure, and says to me that it's not a useful
optimisation at all when you might be creating several thousand
files/s on a filesystem. That will end up IO bound, SSD or not.
Cheers,
Dave.
--
Dave Chinner
dchinner@redhat.com
next prev parent reply other threads:[~2016-02-16 3:35 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <9D046674-EA8B-4CB5-B049-3CF665D4ED64@aevoo.fr>
2015-11-24 20:42 ` Fwd: [newstore (again)] how disable double write WAL Sage Weil
[not found] ` <CA+gn+znHyioZhOvuidN1pvMgRMOMvjbjcues_+uayYVadetz=A@mail.gmail.com>
2015-12-01 20:34 ` Fwd: " David Casier
2015-12-01 22:02 ` Sage Weil
2015-12-04 20:12 ` Ric Wheeler
2015-12-04 20:20 ` Eric Sandeen
2015-12-08 4:46 ` Dave Chinner
2016-02-15 15:18 ` David Casier
2016-02-15 16:21 ` Eric Sandeen
2016-02-16 3:35 ` Dave Chinner [this message]
2016-02-16 8:14 ` David Casier
2016-02-16 8:39 ` David Casier
2016-02-19 5:26 ` Dave Chinner
2016-02-19 11:28 ` Blair Bethwaite
2016-02-19 12:57 ` Mark Nelson
2016-02-22 12:01 ` Sage Weil
2016-02-22 17:09 ` David Casier
2016-02-22 17:16 ` Sage Weil
2016-02-18 17:54 ` David Casier
2016-02-19 17:06 ` Eric Sandeen
2016-02-21 10:56 ` David Casier
2016-02-22 15:56 ` Eric Sandeen
2016-02-22 16:12 ` David Casier
2016-02-22 16:16 ` Eric Sandeen
2016-02-22 17:17 ` Howard Chu
2016-02-23 5:20 ` Dave Chinner
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