Re: is "replaceable" in 3.2 considered stable

[NeilBrown <neilb@suse.de>]

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On Mon, 5 Nov 2012 05:51:18 +0100 (CET) Mikael Abrahamsson <swmike@swm.pp.se>
wrote:

> 
> Hello.
> 
> I have an ubuntu 12.04 system, (running ubuntu kernel 3.2), and I have a 
> drive I want to swap out that has a lot of offline uncorrectable block on 
> my raid6 mdadm-raid with superblock v1.2, the drive is failing.
> 
> I remembered Neil announcing the "replaceable" option, and it seems this 
> came in 3.2 according to <https://lwn.net/Articles/465048/>.
> 
> Has this function as implemented in 3.2 received a lot of testing and can 
> be considered safe for production use, or is it still as said in the 
> email, for testing only?
> 
> My kernel:
> 
> 3.2.0-32-generic #51-Ubuntu SMP Wed Sep 26 21:33:09 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
> 

Try it.  If it works for you, we can be more confident that it is stable :-)

Seriously I think it is safe to try but I won't promise that nothing will go
wrong.  I do promise that if something goes wrong (which is fairly unlikely),
I'll do my best to help you fix it, and think it is extremely unlikely that
the experiment will cause data loss.

One thing to be aware of:  if you need to reboot during the replacement
process, the mdadm you have installed will not be able to put the array back
together properly (it will leave out either the failing device or the
replacement).  The mdadm in the 'master' branch of my git tree can do this so
if it comes to that, there is a way forward.

NeilBrown

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