Re: Removing a failing drive from multiple arrays

[NeilBrown <neilb@suse.de>]

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On Thu, 19 Apr 2012 14:54:30 -0400 Bill Davidsen <davidsen@tmr.com> wrote:

> I have a failing drive, and partitions are in multiple arrays. I'm 
> looking for the least painful and most reliable way to replace it. It's 
> internal, I have a twin in an external box, and can create all the parts 
> now and then swap the drive physically. The layout is complex, here's 
> what blkdevtra tells me about this device, the full trace is attached.
> 
> Block device sdd, logical device 8:48
> Model Family:     Seagate Barracuda 7200.10
> Device Model:     ST3750640AS
> Serial Number:    5QD330ZW
>      Device size   732.575 GB
>             sdd1     0.201 GB
>             sdd2     3.912 GB
>             sdd3    24.419 GB
>             sdd4     0.000 GB
>             sdd5    48.838 GB [md123] /mnt/workspace
>             sdd6     0.498 GB
>             sdd7    19.543 GB [md125]
>             sdd8    29.303 GB [md126]
>             sdd9   605.859 GB [md127] /exports/common
>    Unpartitioned     0.003 GB
> 
> I think what I want to do is to partition the new drive, then one array 
> at a time fail and remove the partition on the bad drive, and add a 
> partition on the new good drive. Then repeat for each array until all 
> are complete and on a new drive. Then I should be able to power off, 
> remove the failed drive, put the good drive in the case, and the arrays 
> should reassemble by UUID.
> 
> Does that sound right? Is there an easier way?
> 

I would add the new partition before failing the old but that isn't a big
issues.

If you were running a really new kernel, used 1.x metadata, and were happy to
try out code that that hasn't had a lot of real-life testing you could (after
adding the new partition) do
   echo want_replacement > /sys/block/md123/md/dev-sdd5/state
(for example).

Then it would build the spare before failing the original.
You need linux 3.3 for this to have any chance of working.

NeilBrown

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