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From: David Casier <david.casier@aevoo.fr>
To: Dave Chinner <dchinner@redhat.com>
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>,
	"Benoît LORIOT" <benoit.loriot@aevoo.fr>
Subject: Re: Fwd: Fwd: [newstore (again)] how disable double write WAL
Date: Tue, 16 Feb 2016 09:14:35 +0100	[thread overview]
Message-ID: <CA+gn+z=dGTeLo71h=z=AvoLM-RRq_-RfbJwFamyfxK93bvk+Hw@mail.gmail.com> (raw)
In-Reply-To: <20160216033538.GB2005@devil.localdomain>

Hi,
All inodes, xattrs and extent are stored at the beginning of the disk
with inode32 XFS ?

2016-02-16 4:35 GMT+01:00 Dave Chinner <dchinner@redhat.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



-- 

________________________________________________________

Cordialement,

David CASIER


3B Rue Taylor, CS20004
75481 PARIS Cedex 10 Paris

Ligne directe: 01 75 98 53 85
Email: david.casier@aevoo.fr
________________________________________________________

  reply	other threads:[~2016-02-16  8:14 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
2016-02-16  8:14                 ` David Casier [this message]
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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