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To: linux-btrfs@vger.kernel.org
From: TM <tmjuju@yahoo.com>
Subject: Re: 1 week to rebuid 4x 3TB raid10 is a long time!
Date: Tue, 22 Jul 2014 14:43:45 +0000 (UTC)
Message-ID: <loom.20140722T164042-111@post.gmane.org>
References: <loom.20140720T102642-239@post.gmane.org> <53CC6B39.1060705@cn.fujitsu.com> <loom.20140721T155907-291@post.gmane.org> <53CDBBC7.6000609@cn.fujitsu.com>
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Wang Shilong <wangsl.fnst <at> cn.fujitsu.com> writes:


> The latest btrfs-progs include man page of btrfs-replace. Actually, you 
> could use it
> something like:
> 
> btrfs replace start  <srcdev>|<devid> <targetdev> <mnt>
> 
> You could use 'btrfs file show' to see missing device id. and then run 
> btrfs replace.
> 

Hi Wang,

  I physically removed the drive before the rebuild, having a failing device
as a source is not a good idea anyway.
  Without the device in place, the device name is not showing up, since the
missing device is not under /dev/sdXX or anything else. 

  That is why I asked if the special parameter 'missing' may be used in a
replace. I can't say if it is supported. But I guess not, since I found no
documentation on this matter.

  So I guess replace is not aimed at fault tolerance / rebuilding. It's just
a convenient way to lets lay replace the disks with larger disks , to extend
your array. A convenience tool, not an emergency tool.

TM

> Thanks,
> Wang