On Thursday 11 January 2007 02:04, Brad L. Chisholm wrote: > On Wed, Jan 10, 2007 at 10:11:38PM -0500, John Baldwin wrote: > > On Wednesday 10 January 2007 19:15, Brad L. Chisholm wrote: > > > > > > I notice the following in the vm.zone output captured just prior to > > > a hang. Does this value correspond to the swap_zone you were referring > > > to? This looks like a limit may have been reached. > > > > > > SWAPMETA: 288, 116519, 116519, 0, 116543 > > > > yep, that's exactly the issue you are hitting. > > > > > I don't seem to be able to query kern.maxswzone on our 6.2-BETA2 image: > > > > > > # sysctl kern.maxswzone > > > sysctl: unknown oid 'kern.maxswzone' > > > > > > Is it available in 6.x, or is it something newer? > > > > It's only a tunable, not available as a sysctl. You can figure out the > > current size from the vmstat output above, then do some math to figure > > out a good guess to use based on how much swap it had in use when it > > locked up. For example, right now you have 116519 objects of size 288, so > > 33557472 bytes allocated. You said you die when 14 GB out of 64 total is > > used, so you should probably try taking that value and multiplying it by > > 64 / 14. That gives a result of 153405586. However, you really want to > > round this up to a multiple of 288 (because the kernel rounds it down to > > a multiple of 288), so I'd use a value of at least 153405792. And yes, > > that means you are setting aside a little over 146 MB of wired, physical > > RAM just to hold metadata for your swap. :) > > > > Excellent! Increasing kern.maxswzone has indeed fixed the problem. Can > this value be auto-tuned better based upon the size of swap, or is it the > particular swapping pattern caused by our environment that caused the > default size to be insufficient? In any case, the kernel printf you added > recently should help make this much easier to diagnose in the future. > > Thanks for your help!
The kernel does do a guess, but it doesn't always get the guess right, and I think there might be a bug where it always guesses wrong for > 32GB of swap. :) -- John Baldwin _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "[EMAIL PROTECTED]"
