also sprach Hal Vaughan <hal@thresholddigital.com> [2007.08.18.1051 +0200]:
> a 2nd drive failed. I shut it down, got some new drives (bigger to be
> sure they weren't too small, allowing for differences in drive sizes
> reported by drive makers), replaced the bad drives, and rebuilt the
> spare with no problem at all.
Are you certain the rebuild was completed? Did you --add the drives
to the array after --remove'ing the broken ones?
> State : active, degraded
[...]
> 0 0 0 - removed
> 1 0 0 - removed
> 2 34 0 2 active sync /dev/hdg
This does not look like you did.
> I notice the information changes from drive to drive and is
> inconsistent.
The reason for this is that some of the drives' superblocks have
not been updated because you did not --add them.
I hope you have backups. Otherwise I doubt you'll get your data back
easily.
also sprach Mike Bird <mgb-debian@yosemite.net> [2007.08.18.1537 +0200]:
> 3) RAID 5 is not resilient against multiple failures. We now use RAID 1.
> RAID 1 is also faster, although it sometimes requires more drives.
> In extreme cases we use RAID 1 with three or more drives.
RAID 1 is also not resilient to multiple failures.
> 4) With four drives, rather than RAID 5 with a hot spare, I would create
> two RAID 1 arrays. One could then combine them in RAID 0 or linear
> but I would choose to make them be PVMs in a LVM VG.
... or use RAID 10, if you don't need LVM otherwise. You'll get
better performance with RAID 10 than with RAID1+LVM (or RAID1+linear
or RAID1+RAID0 for that matter).
--
.''`. martin f. krafft <madduck@debian.org>
: :' : proud Debian developer, author, administrator, and user
`. `'` http://people.debian.org/~madduck - http://debiansystem.info
`- Debian - when you have better things to do than fixing systems
tempt not a desperate man.
-- william shakespeare
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