*BSD News Article 59749


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From: graichen@dirac.physik.fu-berlin.de (Thomas Graichen)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Re: 2 swap devices: does it make sense?
Date: 16 Jan 1996 12:32:55 GMT
Organization: Freie Universitaet Berlin
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References: <87u41zetl7.fsf@compi.hobby.nl> <4denac$re@vulture.dmem.strath.ac.uk> <MICHAELV.96Jan16000702@MindBender.HeadCandy.com>
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Michael L. VanLoon (michaelv@MindBender.HeadCandy.com) wrote:
: In article <4denac$re@vulture.dmem.strath.ac.uk> nbc@vulture.dmem.strath.ac.uk (Neil Brendan Clark) writes:

:    Peter Mutsaers <plm@compi.hobby.nl> wrote:
:    >If I define 2 swap devices, each on a different disk, and I'm doing
:    >heavy disk I/O: will both swap devices be used by FreeBSD 2.1 to
:    >divide the disk I/O over the two disks?

:    Swap devices are interleaved, so the answer is yes. How effective this
:    strategy is would (I imagine) depend on your hard disks; for example, I
:    am unsure how useful two IDE disks would be since CPU time is used by
:    data transfers, but SCSI drives would give a definite improvement. At least,
:    that is, if the world is a fair place ;-)

: Three SCSI drives, each with a 32MB swap partition, work just great on
: my system (with a BusLogic bt747 EISA controller), yes...

also two IDE drives (each on its own controller) are also better than one
:-) 

t
  _______________________________________________________||___________________
                                                   __||
  Perfection is reached, not when there is no  __||     thomas graichen
  longer anything to add, but when there   __||    freie universitaet berlin
  is no longer anything to take away   __||           fachbereich physik
                                   __||                      
  - Antoine de Saint-Exupery - __||        graichen@mail.physik.fu-berlin.de
  ___________________________||__________________graichen@FreeBSD.org_________