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Re: Question about memory use in Linux

On Sat, Nov 03, 2001 at 08:18:35PM +0000, Aniartia wrote:
> Adding a 2nd swap file on a disk seems counter productive as you've not got 2
> stores and unless the swap priorty is the same will jump between then making
> things slower. I don't understand swap priortys but to say you can tell linux
> to swap to 1 partition in prefrence to another.

You've got this backwards.  If the priorities are the same, the
kernel will try to use all partitions simultaneously.  If they're
different, it fills one up before going to the other.

In any case, though, having multiple swap partitions on the same
physical drive rarely makes any sense.  Just make one bigger swap

> Multi-swap partitions on seperate disks can make swap faster but on IDE disks
> it seems to be more of a hinderence than a benafit, SCSI seems to benafit
> from havin' swap distrubuted over serveral drives.

On IDE, you'll see a performance benefit if each of the drives
holding swap is on a different IDE controller.  If you have two swap
partitions on the same controller (whether they're on the same drive
or one is on master and the other is on slave) with the same
priority, that will kill your performance because of the way IDE

With SCSI, OTOH, the drives are smarter so, provided you don't exceed
the available bandwidth on your SCSI bus, you can simultaneously use
as many drives as you want without penalty.

When we reduce our own liberties to stop terrorism, the terrorists
have already won. - reverius

Innocence is no protection when governments go bad. - Mr. Slippery

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