*BSD News Article 88265


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From: jun@goten.sinfony.ad.jp (Junichi Kurokawa)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Re: FreeBSD does interleaved paging : faster?
Date: 04 Feb 1997 07:11:05 GMT
Organization: Sony Systems Design Corp., Takanawa, Tokyo
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Message-ID: <JUN.97Feb4161105@goten.sinfony.ad.jp>
References: <JUN.97Feb4100600@goten.sinfony.ad.jp>
 <32F6BA44.2DA758F0@indiana.edu>
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In-reply-to: Lars Hofhansl's message of 04 Feb 1997 13:25:42 +0900
Xref: euryale.cc.adfa.oz.au comp.unix.bsd.freebsd.misc:35008

In article <32F6BA44.2DA758F0@indiana.edu>
Lars Hofhansl <lhofhans@indiana.edu> writes:

  >Junichi Kurokawa wrote:
  >> 
  >> The subject says it all....
  >> 
  >> With dedicated hardwares e.g. Suns, I occasionally hear that interleaved
  >> swap partitions improve paging performance.
  >> 
  >> But how about the case with a ubiquitous PC MB plus *signle channel*
  >> SCSI a la AHA2940, and FreeBSD?  Is it faster?
  >> 
  >> Your comments are welcomed, thanks!
  >> 
  >> Regards,
  >> junichi
  >
  >It's definately faster if you use seperate _disks_ (assuming all
  >the disk are about the same speed).

Separate across what?  Do you mean to divide the swap across the drives, 
or swap in sd0a and /usr in sd1a or similar as you mention below?

  >On an older system I had swap and /usr on different disk, which
  >gave quite a preformance gain.

This makes sense.  I'll try it.

BTW where did you put your /home, a busy partition as well?  In the swap
drive, the /usr drive or even in a third drive?  This is crucial.

  >Having serveral swappartitions of different disks should give
  >some performance gain also, since it (in the best case) halfs the
  >seektime (since the seeks can be done in parallel) as seen by the
  >operating system (the "page latency" of course is unchanged, and the
  >throughput may and may not by changed).

This was my first intension in the Q.

I thank Lars for his comments, and welcome more comments on the subject
from others.

Regards,
junichi