Re: Two Drive Failure on RAID-5

[Cry <cry_regarder@yahoo.com>]

David Greaves <david <at> dgreaves.com> writes:

> 
> Yep. Don't panic and don't do anything else yet if you're not confident about
> what you're doing.
> 
> I'll follow up with more info in a short while.
> 
> Info you can provide:
> kernel version
> mdadm version
> cat /proc/mdstat
> mdadm --examine /dev/sd[abcdef]1 (or whatever your array components are)
> relevant smartctl info on the bad drive(s)
> dmesg info about the drive failures
> 
> Assuming genuine hardware failure:
> Do you have any spare drives that you can use to replace the components?
> 
> David

Thanks for the info.  I was able to do a --force --assemble on the array and I
copied off my most critical data.  At the moment, I don't have enough drives to
take all the data on the array, so I'm going to be at a bit of a standstill
until new hardware arrives.

Since the copy of that data (about 500Gig of about 2TB) went so well, I decided
to try to sync up the spare again and it died at the same point and the raid
system pulled down the array.  I'm trying to decide if I should follow your
suggestion in sister post to copy the failed drive onto my spare or if I should
just format the spare and try to recover another 500 gig of data of the array.

Is there a mdadm or other command to tell the raid system to stay up in the face
of errors?  Can the array be assembled in a way that doesn't change the array in
any way (completely read-only)?

I've got the older failed drive also (about 15 hours older).  Can that be
leveraged also?

The server isn't networked right now, but I'll try to get the above requested
logs tonight.

By the way, I'm thinking about buying five of these:

Seagate Barracuda 7200.11 1TB ST31000340AS SATA-II 32MB Cache

and one of these:

Supermicro SUPERMICRO CSE-M35T-1 Hot-Swapable SATA HDD Enclosure

http://www.supermicro.com/products/accessories/mobilerack/CSE-M35T-1.cfm

and building a raid-6 array.  I'll convert the surviving drives into a backup
for the primary array.  Any feedback on the above?  Is there a suggestion on an
inexpensive controller to give more SATA ports that is very software raid
compatible?

Any suggestions for optimal configuration (ext3) and tuning for the new array? 
My load consists of serving a photo gallery via apache and gallery2 as well as a
local media (audio/video) server so files sizes tend to be large.

Thanks,

Joel