Re: [PLUG] Pros and cons of swap in a partition vs. in a file in the file system

["David Colon" <dcolon@dcolon.org>]

> We've done this where I work, on occasion.  We have some commercial apps
> (aren't they always the problem children?) that insist on having x
> amount of swap space available on the system, regardless of whether
> there's ever any real chance of even touching it.  So we use dd to
> create a big file of the size needed, mkswap it, and swapon it at a
> priority level that it'll never get used.  Badly behaved commercial apps
> are happy, and the only thing we're out is some disk space that'll never
> get touched.  Shoot...if you can swing a way to create the file as a
> sparse file, there's a pretty good chance that most of that disk space
> will never actually get allocated anyway!

     Ugh, Oracle is such a commercial app.  On a machine with 16 gigs
of RAM, the installer won't run if you don't have 16 or 32 gigs of
swap.  Oracle support is the same way.  We have machines that had
Oracle installed when the machine had  8 gigs of RAM and swap.  We
later upgraded the machine to 16 gigs of RAM and left the swap as is
because it was never used.  Recently, our DBAs had to open a case with
Oracle because one of the databases kept crashing.  Oracle blamed the
crashes on the fact that there wasn't enough swap even though sysstat
and other output showed that swap was never being used.  I created a
swap file to bring the total up to 16 gigs and the crashes continued.
I'm waiting to hear their next response.

David
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