On Tue, Jul 02, 2002 at 11:12:03AM +0200, Zwane Mwaikambo wrote:
> On Tue, 2 Jul 2002, Helge Hafting wrote:
>
> > > > /dev/md1 swap swap defaults 0 0
> > >
> > > One small thing, you do know that you can interleave swap?
> >
> > There are sometimes reasons not to do that.
> > Heavy swapping may be caused by attempts to cache
> > massive io on some fs. You better not have swap
> > on that heavily accessed spindle - because then
> > everything ends up waiting on that io.
> >
> > Keeping swap somewhere else means other programs
> > just wait a little for swap - undisturbed by the massive
> > io also going on.
>
> True, but what i meant was that instead of creating a RAID device to swap
> to, he could have just interleaved normal swap partitions and gotten the
> same effect.
Not a config i would recommend. While spreading swap over
multiple spindles that way is good for speed it multiplies the
likelihood that a disk failure will down the system. If you
think a dead filesystem is a mess, just watch what happens
when swap goes dead.
Much better to put swap on several RAID-1 volumes if
you want to spread it around. Disks just aren't that
expensive anymore. RAID-5 though would be a bad move since
swap gets an order of magnitude more writes than reads. On
account of the heavy write tendencies i lean toward
so-called hardware RAID for swap in order to offload the PCI
buss.
-- ________________________________________________________________ J.W. Schultz Pegasystems Technologies email address: jw@pegasys.wsRemember Cernan and Schmitt - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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