> 2. If you are on a platform where the kernel thinks it can swap out
> parts of shared memory (which is most platforms, these days), it's
> counterproductive to make your shared mem large enough that it's not
> all being used heavily. If the kernel decides to swap out some buffer
> space, you have a net loss in performance, because you just wasted
> disk I/O (especially if the page in the buffer is dirty --- it'll
> eventually have to be read in again, then written out again, to no
> purpose).
FYI, FreeBSD had the ability to disable shared memory swapping with a
sysctl setting, while BSD/OS does not swap out shared memory.
--
Bruce Momjian | http://candle.pha.pa.us
pgman@candle.pha.pa.us | (610) 853-3000
+ If your life is a hard drive, | 830 Blythe Avenue
+ Christ can be your backup. | Drexel Hill, Pennsylvania 19026
