[ale] who is eating my drive

[Jim Kinney]

On Tue, May 31, 2011 at 3:45 PM, Pat Regan <thehead at patshead.com> wrote:

> On Tue, 31 May 2011 15:34:05 -0400
> Jim Kinney <jim.kinney at gmail.com> wrote:
>
> > On Tue, May 31, 2011 at 3:04 PM, Pat Regan <thehead at patshead.com>
> > wrote:
> >
> > > On Tue, 31 May 2011 14:49:53 -0400
> > > Jim Kinney <jim.kinney at gmail.com> wrote:
> > >
> > > > swap notes: NEVER put swap on a raid5. If you must park swap on a
> > > > RAID rig, mirrored partitions are OK. If swap gets hosed, the box
> > > > crashes. The RAID5/6 writes for swap are performance killers. Swap
> > > > will do it own striping so don't bother doing a raid10. multiple
> > > > swap parts on multiple drive spindles is a good thing. Say 8G RAM
> > > > and 4 1TB drives, set up a 4G swap on each of the drives.
> > >
> > > Putting swap on RAID also means that your server won't go down due
> > > to a disk failure.
> > >
> >
> > Swap on RAID5/6 means during a rebuild the disk IO times out on swap
> > retrieval and the kernel panics thinking the swap is down.
>
> I have never had this happen, although I can only recall one time that
> I've ever had swap on a RAID 5.  It was a hardware RAID 5 and was the
> only disk available.
>
> Is this only a problem with software RAID?  I'd be surprised if it is...
>
> In your experience with this situation, where exactly is the timeout
> happening?
>

Saw this fail once a while back. swap on a hardware raid5 that lost a drive.
the last line on the screen before the lockup was
kernel panic swap error
after the dead drive was replaced (hot swap setup) and the system was still
running during the recovery.

OK. So maybe the hardware could detect I'm no fan of RAID5 in any form and
dislike hardware in most forms and just decided to take a dump because I was
standing there.

>
> Pat
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-- 
-- 
James P. Kinney III

As long as the general population is passive, apathetic, diverted to
consumerism or hatred of the vulnerable, then the powerful can do as they
please, and those who survive will be left to contemplate the outcome.
- *2011 Noam Chomsky*
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