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From: John Robinson <john.robinson@anonymous.org.uk>
To: SandeepKsinha <sandeepksinha@gmail.com>
Cc: Linux RAID <linux-raid@vger.kernel.org>
Subject: Re: RAID5 reconstruction ?
Date: Sat, 30 May 2009 14:35:14 +0100	[thread overview]
Message-ID: <4A213612.7080206@anonymous.org.uk> (raw)
In-Reply-To: <37d33d830905292244w685499b3h391aa2ca7a5b1ad@mail.gmail.com>

On 30/05/2009 06:44, SandeepKsinha wrote:
> Hi all,
> 
> Say If I have a RAID 5 array of 50GB of five disks of 10GB each.
> 
> I have data of 5GB. When a disk fails and replaced with a spare disk.
> Will the reconstruction happen only for the 5GB allocated disk blocks
> or it will happen for the whole disk size.

The whole disc size, for now anyway; md does not currently note which 
blocks have been used by its client (the filesystem, LVM, whatever).

> Is it possible to make  reconstruction intelligent enough to keep it optimized ?

This has been discussed in combination with supporting SSD drives' TRIM 
function, and would mean md had to keep track of used chunks or possibly 
even sectors using a bitmap or something like that, but whether anyone's 
working on it I don't know.

Cheers,

John.


  parent reply	other threads:[~2009-05-30 13:35 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-30  5:44 RAID5 reconstruction ? SandeepKsinha
2009-05-30 12:52 ` Sujit Karataparambil
2009-05-30 13:28   ` SandeepKsinha
2009-05-30 13:31     ` Sujit Karataparambil
2009-06-09  4:13   ` Nifty Fedora Mitch
2009-05-30 13:35 ` John Robinson [this message]
2009-05-30 14:06   ` Maxime Boissonneault
2009-05-30 15:46     ` John Robinson
2009-05-30 16:16       ` Maxime Boissonneault
2009-05-30 16:30         ` John Robinson
2009-05-30 16:08   ` Redeeman
2009-05-30 18:39     ` Bill Davidsen
2009-05-30 18:54     ` Goswin von Brederlow
2009-05-31  8:10       ` SandeepKsinha
2009-05-30 18:55     ` Goswin von Brederlow
2009-05-30 19:37       ` Redeeman
2009-05-31  8:02         ` SandeepKsinha
2009-05-31 11:54           ` Goswin von Brederlow
2009-05-31 12:11             ` John Robinson
2009-05-31 12:14             ` NeilBrown
2009-06-03  1:54               ` Greg Freemyer
2009-06-02 18:42       ` Bill Davidsen

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