on 10/8/2007 6:03 AM Tony Mountifield spake the following:
In article <47098D7B.9020104@xxxxxxxxx>,
Les Mikesell <lesmikesell@xxxxxxxxx> wrote:
The only tricky part is what happens to the drive names if you boot with
/dev/sda broken (depending on the failure mode) or missing. If the
controller doesn't see it, all of the other drive names will shift up.
This normally won't affect md device detection, but you may have a non
md device mentioned in /etc/fstab, especially for swap devices.
I normally put swap on a /dev/mdN device too. I have seen different people
say you should and you shouldn't, but my reasoning is this: if I have swap
just on raw partitions, e.g. /dev/sda2 and /dev/sdb2, what happens if a
drive dies while running programs are partly swapped out to the failed
drive? I expect at least that the programs would die, and at worst I might
get a kernel panic.
But if I am swapping to /dev/md2 that contains /dev/sda2 and /dev/sdb2 in
a RAID1 mirror, the swapped-out data is preserved on a drive failure, and
the programs should be able to keep running.
Swapping to /dev/mdN certainly seems to work fine, but I haven't yet had
a drive failure to test!
Cheers
Tony
When I use software raid I always use a mirrored swap partition. It is a
little slower, but if you lose a drive, the system won't boink.
Otherwise, the system will panic if it can't get back from the swap. Of course
the best way it to have enough memory that you don't need swap.
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