Re: Swap Space needed on Solaris 8,10

Greg wrote:
> Most of the documentation you see about setting swap space for an
> Oracle box states that swap should be equal to RAM. With the size of
> RAM now days getting to 64Gig or more, is this really a requirement?
> Is there a good standard to follow?
>
> I have also read that Sun allocates swap at the same time and amount as
> it allocates RAM for a process. Is this still true with Solaris 8 and
> 10? If so, I can see why you might set swap equal to RAM.
>

See Note 17094.1 on Metalink, "Unix Virtual Memory, Paging & Swapping explained".

The old ROT was that swap should be 2-3 times physical RAM. Don't make the mistake of thinking that swap space resides exclusively on disk -- swap can comprise physical RAM also.

Excerpt from note:

"The bottom line is, that while it is possible to estimate virtual and   physical memory usage on a UNIX machine, doing so is more of an art   than a science.

"First: you must measure your actual application.[...]

"Second: when measuring physical memory usage, make sure that your   system is as heavily loaded as it will be in a production situation."

-Mark Bole Received on Fri Aug 12 2005 - 11:51:37 CDT