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From: Gordan Bobic <gordan@bobich.net>
To: BTRFS MAILING LIST <linux-btrfs@vger.kernel.org>
Subject: Re: Offline Deduplication for Btrfs
Date: Wed, 05 Jan 2011 20:25:41 +0000	[thread overview]
Message-ID: <4D24D3C5.6080803@bobich.net> (raw)
In-Reply-To: <201101051941.13268.diegocg@gmail.com>

On 01/05/2011 06:41 PM, Diego Calleja wrote:
> On Mi=E9rcoles, 5 de Enero de 2011 18:42:42 Gordan Bobic escribi=F3:
>> So by doing the hash indexing offline, the total amount of disk I/O
>> required effectively doubles, and the amount of CPU spent on doing t=
he
>> hashing is in no way reduced.
>
> But there are people who might want to avoid temporally the extra cos=
t
> of online dedup, and do it offline when the server load is smaller.

The point is that the offline dedup is actually twice as expensive, and=
=20
the hashing part is nowhere nearly expensive as disk I/O. Disk I/O is=20
very limited today, compared to CPU time.

Gordan
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  parent reply	other threads:[~2011-01-05 20:25 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-01-05 16:36 Offline Deduplication for Btrfs Josef Bacik
2011-01-05 16:36 ` [PATCH] Btrfs: add extent-same ioctl for dedup Josef Bacik
2011-01-05 17:50   ` Simon Farnsworth
2011-01-05 16:36 ` [PATCH] Btrfs-progs: add dedup functionality Josef Bacik
2011-01-05 17:42 ` Offline Deduplication for Btrfs Gordan Bobic
2011-01-05 18:41   ` Diego Calleja
2011-01-05 19:01     ` Ray Van Dolson
2011-01-05 20:27       ` Gordan Bobic
2011-01-05 20:28       ` Josef Bacik
2011-01-05 20:25     ` Gordan Bobic [this message]
2011-01-05 21:14       ` Diego Calleja
2011-01-05 21:21         ` Gordan Bobic
2011-01-05 19:46   ` Josef Bacik
2011-01-05 19:58     ` Lars Wirzenius
2011-01-05 20:15       ` Josef Bacik
2011-01-05 20:34         ` Freddie Cash
2011-01-05 21:07       ` Lars Wirzenius
2011-01-05 20:12     ` Freddie Cash
2011-01-05 20:46     ` Gordan Bobic
     [not found]       ` <4D250B3C.6010708@shiftmail.org>
2011-01-06  1:03         ` Gordan Bobic
2011-01-06  1:56           ` Spelic
2011-01-06 10:39             ` Gordan Bobic
2011-01-06  3:33           ` Freddie Cash
2011-01-06  1:19       ` Spelic
2011-01-06  3:58         ` Peter A
2011-01-06 10:48           ` Gordan Bobic
2011-01-06 13:33             ` Peter A
2011-01-06 14:00               ` Gordan Bobic
2011-01-06 14:52                 ` Peter A
2011-01-06 15:07                   ` Gordan Bobic
2011-01-06 16:11                     ` Peter A
2011-01-06 18:35           ` Chris Mason
2011-01-08  0:27             ` Peter A
2011-01-06 14:30         ` Tomasz Torcz
2011-01-06 14:49           ` Gordan Bobic
2011-01-06  1:29   ` Chris Mason
2011-01-06 10:33     ` Gordan Bobic
2011-01-10 15:28     ` Ric Wheeler
2011-01-10 15:37       ` Josef Bacik
2011-01-10 15:39         ` Chris Mason
2011-01-10 15:43           ` Josef Bacik
2011-01-06 12:18   ` Simon Farnsworth
2011-01-06 12:29     ` Gordan Bobic
2011-01-06 13:30       ` Simon Farnsworth
2011-01-06 14:20     ` Ondřej Bílka
2011-01-06 14:41       ` Gordan Bobic
2011-01-06 15:37         ` Ondřej Bílka
2011-01-06  8:25 ` Yan, Zheng 
  -- strict thread matches above, loose matches on Subject: below --
2011-01-06  9:37 Tomasz Chmielewski
2011-01-06  9:51 ` Mike Hommey
2011-01-06 16:57   ` Hubert Kario
2011-01-06 10:52 ` Gordan Bobic
2011-01-16  0:18 Arjen Nienhuis

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