NeilBrown wrote:

On Thu, 19 Apr 2012 14:54:30 -0400 Bill Davidsen[off-list ref]  wrote:

quoted

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.

Seems I got this a day late, but I will happily do some testing in real 
world conditions when I get another replacement drive, since I noted 
some issues in another drive.

Kernel is 3.3.1-5 in Fedora 16, should have mentioned that, I guess.

Thanks for the input, wonder why multiple drives are dying, coincidence 
or some other problem? I did check the p/s, voltages are all good, 
minimal ripple, no spikes, surge protection and UPS on the power, etc.


-- 
Bill Davidsen [off-list ref]
   "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot