On Mon, 16 Nov 2009, Robin Hill wrote:

Are you running any regular array checks?  These should verify the 
readability of the drives (and accuracy of the checksums).  This type of 
failure's also why I've switched to RAID6 for most of my arrays.

Yes, I'm running those checks (ubuntu default) and the array was fine a 
week ago. I learnt that a few years back how important that is.

Technically, the best practice is probably to recreate the array from
scratch (replacing any failed drives) and restore from backup.  Short of
that, your approach would seem to be the best option.  I've done this in
the past, though I ended up restoring pretty much everything from backup
anyway (as I had no other way of verifying the integrity of the data).

Well, I don't really have a full backup and integrity of the files isn't a 
real priority, so if I would have corrupted a few files it doesn't matter.

I'd leave that to later.  Once you've imaged the disk you can try SMART 
tests, read/write tests, etc. to verify whether there's actually a 
physical problem or not (and how much of one - a bad block or two might 
be acceptable, but a lot of them would point to a failing disk).  Until 
then you're better putting as little trust in the disk as possible.

There is a problem with the drive, it's been having bad blocks before 
which has been remapped (during the check phase), I was going to get it 
replaced on warranty and I even purchased a replacement but before I got 
around to all this, I ended up with a total of 2 completey dead drives and 
one with errors.

I'm seriously considering going RAID6, been pondering it for quite a 
while, only thing that kept me back was that I wanted to migrate to RAID6 
but the code wasn't really ready (as has been discussed here before).

-- 
Mikael Abrahamsson    email: swmike@swm.pp.se