Re: RHEL3 swapping too much (was Re: Monitoring Memory)

[Al Tobey <albert tobey priority-health com>]

These settings seem to alleviate the swapping of my apache processes
(that are/were suffering from an app leaking memory under mod_perl):

vm.bdflush = 10 1000 500 5000 0 6000 100 0 0
vm.overcommit_memory = 0
vm.overcommit_ratio  = 75

I don't remember the exact logic I used to come up with these settings,
but the box started behaving better immediately once these were applied.

I will also try the vm.pagecache options.

-Al Tobey

On Thu, 2004-06-10 at 15:19, Christopher McCrory wrote:
> Hello...
> 
> On Thu, 2004-06-10 at 09:54, Kevin Stussman wrote:
> > Yeah, we're looking into this vm option...Did you find it to help the
> > system swap less?
> > 
> 
> Yes
> 
> On dual P4 3.2Ghz zeon w/ 4 gig ram only running apache with a 30M
> footprint we were _swapping out apache_ .  The only meaningful ($$$)
> process was being swapped!  $# %!$#
> 
> On RH7.3 turning off swap worked fine, on RHEL3 turning off swap seems
> to increase load. ? ? ?
> 
> 
> 
> > Found these to be helpful as well. 
> > 
> > http://www.redhat.com/advice/tips/meminfo.html
> > http://www.redhat.com/whitepapers/rhel/OracleonLinux.pdf
> > https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=118706
> > https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=124576
> > 
> > Regards,
> > 
> > Kevin
> > 
> > 
> > On Wed, 2004-06-09 at 18:21, Christopher McCrory wrote:
> > > On Wed, 2004-06-09 at 16:46, Kevin Stussman wrote:
> > > > I have been looking at /proc/meminfo and /proc/slabinfo trying to figure
> > > > out what is meaning to a swapping problem that we are experiencing. It
> > > > seems like we have tons of cache memory, but when new memory is needed
> > > > the OS starts to swap.
> > > > 
> > > 
> > > https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=89226
> > > 
> > > 
> > > [chrismcc@ chrismcc]$  tail /etc/sysctl.conf
> > >  
> > > # Controls whether core dumps will append the PID to the core filename.
> > > # Useful for debugging multi-threaded applications.
> > > kernel.core_uses_pid = 1
> > > # "Just In Case", reboot on panic
> > > kernel.panic = 1
> > >  
> > > # temporary
> > >  
> > > vm.pagecache = 1 10 20
> > > 
> > > 
> > > 
> > > 
> > > > By using the meminfo and slabinfo, what are some meaningful values to be
> > > > monitoring? I'm trying to make some sense of how things add up but i'm
> > > > not having much luck beyond the basics. For example, I would have
> > > > thought that (Inactive + Active + Free) = Total or something like that,
> > > > but no (these values will end up on a graph in cacti).
> > > > 
> > > > The documentation for the fields in meminfo and slabinfo is not very
> > > > good and for this monitoring tool, I cannot use sar or free (it has to
> > > > be file based hence /proc).
> > > > 
> > > > Regards,
> > > > 
> > > > Kevin.
> > > > 
> > > > --------------
> > > > 
> > > >         total:    used:    free:  shared: buffers:  cached:
> > > > Mem:  6208667648 6173192192 35475456        0 66961408 5790060544
> > > > Swap: 8587108352 265879552 8321228800
> > > > MemTotal:      6063152 kB
> > > > MemFree:         34644 kB
> > > > MemShared:           0 kB
> > > > Buffers:         65392 kB
> > > > Cached:        5552276 kB
> > > > SwapCached:     102080 kB
> > > > Active:        4612504 kB
> > > > ActiveAnon:    2542240 kB
> > > > ActiveCache:   2070264 kB
> > > > Inact_dirty:    892520 kB
> > > > Inact_laundry:  140268 kB
> > > > Inact_clean:    127828 kB
> > > > Inact_target:  1154624 kB
> > > > HighTotal:     5242816 kB
> > > > HighFree:        16132 kB
> > > > LowTotal:       820336 kB
> > > > LowFree:         18512 kB
> > > > SwapTotal:     8385848 kB
> > > > SwapFree:      8126200 kB
> > > > HugePages_Total:     0
> > > > HugePages_Free:      0
> > > > Hugepagesize:     2048 kB
> > > > 
> > > > 
> > > > 
> > > > --
> > > > Taroon-list mailing list
> > > > Taroon-list redhat com
> > > > http://www.redhat.com/mailman/listinfo/taroon-list



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