Re: oom_killer

On Fri, Apr 22, 2011 at 4:03 AM, Cédric Villemain
<cedric(dot)villemain(dot)debian(at)gmail(dot)com> wrote:
> 2011/4/21 Tory M Blue <tmblue(at)gmail(dot)com>:
>> On Thu, Apr 21, 2011 at 7:27 AM, Merlin Moncure <mmoncure(at)gmail(dot)com> wrote:
>>> On Thu, Apr 21, 2011 at 3:28 AM, Tory M Blue <tmblue(at)gmail(dot)com> wrote:
>>
>>>> Fedora 12
>>>> 32gig memory, 8 proc
>>>> postgres 8.4.4, slony 1.20
>>>> 5 gigs of swap (never hit it!)
>>>
>>> curious: using 32/64 bit postgres? what are your postgresql.conf
>>> memory settings?
>>>
>>> merlin
>>>
>>
>> 32bit
>> 32gb
>> PAE kernel
>>
>> # - Checkpoints -
>> checkpoint_segments = 100
>> max_connections = 300
>> shared_buffers = 2500MB       # min 128kB or max_connections*16kB
>> max_prepared_transactions = 0
>> work_mem = 100MB
>> maintenance_work_mem = 128MB
>> fsync = on
>>
>
> I didn't understand what value you set for vm.overcommit parameters.
> Can you give it and the values in /proc/meminfo, the interesting one
> are "Commit*" ?
>
> If you have strict rules(overcommit=2), then your current kernel
> config may need some love : the commit_limit is probably too low
> because you have a small swap partition. One way is to change :
> vm.overcommit_ratio.
> By default it should be something like 21GB (0.5*32+5) of
> commit_limit, and you probably want 32GB :)
>
> Maybe you have some minor changes in your install or application usage
> and you just hit the limit.

Thanks Cedric

the sysctl vm's are

# 04/17/2011 to keep overcommit memory in check
vm.overcommit_memory = 2
vm.overcommit_ratio = 0

CommitLimit: 4128760 kB
Committed_AS: 2380408 kB

Ya I do think my swap space is biting us, (but again just starting to
grasp that my swap space which has not grown with the continued
addition of memory). I am just not starting to learn that the swap
does need to be properly sized whether it's being used or not. I
figured it would use the swap and it would run out, but sounds like
the system takes the size into consideration and just decides not to
use it.

I appreciate the totally no postgres responses with this.

Thanks
Tory