Hi Bob! Thanks for the input. Is it such that the kernel will never try to give out more shared mem than it physically has then? If so then this is a lot less alarming and I can move on to other things. I just remember seeing tuning info for share mem saying the max should be 90% of physical ram.
-Corey On Thu, Nov 5, 2009 at 8:41 PM, Bob Arendt <[email protected]> wrote: > I believe shmmax is a limit, preventing a single process from > using more more than this. This sounds like it's essentially > unlimited. There's no performance impact, unless the sum of > all shared mem (see ipcs) becomes significant and performance > degrades. On the other hand, if a lower limit is set and an > application requires more shared mem than allowed by shmmax, > the allocation (and application) would fail, which can be > very undesirable. > > Limiting shmmax might limit swapping indirectly, by inhibiting > the operation of processes (via failure). I think it would be > better to manage system load in other ways. > > Cheers, > -Bob Arendt > > > On 11/05/09 00:43, Corey Kovacs wrote: > >> Looking at some 64 bit machines I have running RHEL5.4, I noticed that >> the shmmax settings in sysctl.conf are getting set to 64GB. The machines >> only have from 16 to 32GB. Is this normal on a 64bit load? Seems like a >> good way to end up swapping. >> >> Corey >> > > _______________________________________________ > rhelv5-list mailing list > [email protected] > https://www.redhat.com/mailman/listinfo/rhelv5-list >
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