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From: grr@cbmvax.commodore.com (George Robbins)
Newsgroups: comp.unix.ultrix
Subject: Re: A question about swap
Keywords: swap
Message-ID: <22528@cbmvax.commodore.com>
Date: 18 Jun 91 08:53:14 GMT
References: <1991Jun14.184609.21178@mlb.semi.harris.com> <967@lhdsy1.chevron.com> <1991Jun18.042752.10818@rata.vuw.ac.nz>
Reply-To: grr@cbmvax.commodore.com (George Robbins)
Organization: Commodore, West Chester, PA
Lines: 37

In article <1991Jun18.042752.10818@rata.vuw.ac.nz> ellis@rata.vuw.ac.nz (Brian Ellis) writes:
> In article <967@lhdsy1.chevron.com>, yzarn@lhdsy1.chevron.com (Philip Yzarn de Louraille) writes:
> |> In article <1991Jun14.184609.21178@mlb.semi.harris.com> dcb@dave.mis.semi.harris.com writes:
> |> >On one of our 5500s, we have configured over 500M of swap space. Someone
> |> >recommended using the 'a' and 'b' partitions over five drives, with the
> |> >a/b partitions combined into a larger 'a' partition.
> |> ... deleted text...

> |> I was told once to *never* mess up with the a partition of a disk.
> |> Forget about the 16Meg you will be loosing.
> 
> Referring to the guide to Configuration file maintenance...
> 
> "Avoid selecting partition a of any disk for use as the swap partition. If
> partition table information was defined for a disk and swapping occurs on the
> a partition, the information is destroyed and data is lost."
> 
> Given that either the "a" or the "c" partition may be the "root" partition
> of the disk, I would be *very* wary of using the c partition for the same
> reasons. 

Well, I would be wary of changing the "c" parition to anything other than the
whole drive and then using it for swap space.  As long as you are really planning
on using the whole drive, the worst that can happen is you blow away the (putative)
partition table and Ultrix reverts to using the parition information coded in the
disk driver, which incidentally will have "c" as the whole drive.

On the other hand, I would prefer to config the kernal to swap on "b" and then
chpt the "b" partition to whatever size I wanted.  This makes changing the swap
an operational task instead of requring a new config and avoids violating the
principle of least surprise, lest a co-worker other person get stuck with doing
a post-mortem on your system.

-- 
George Robbins - now working for,     uucp:   {uunet|pyramid|rutgers}!cbmvax!grr
but no way officially representing:   domain: grr@cbmvax.commodore.com
Commodore, Engineering Department     phone:  215-431-9349 (only by moonlite)