Re: oom_killer

2011/4/22 Cédric Villemain <cedric.villemain.debian@gmail.com>:
> 2011/4/22 Tory M Blue <tmblue@gmail.com>:
>> On Fri, Apr 22, 2011 at 4:03 AM, Cédric Villemain
>> <cedric.villemain.debian@gmail.com> wrote:
>>> 2011/4/21 Tory M Blue <tmblue@gmail.com>:
>>>> On Thu, Apr 21, 2011 at 7:27 AM, Merlin Moncure <mmoncure@gmail.com> wrote:
>>>>> On Thu, Apr 21, 2011 at 3:28 AM, Tory M Blue <tmblue@gmail.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
>
> Are you sure it is a PAE kernel ? You look limited to 4GB.
>
> I don't know atm if overcommit_ratio=0 has a special meaning, else I
> would suggest to update it to something like 40% (the default), but

default being 50 ...

> 60% should still be safe (60% of 32GB + 5GB)
>
>>
>>
>> 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
>>
>
>
>
> --
> Cédric Villemain               2ndQuadrant
> http://2ndQuadrant.fr/     PostgreSQL : Expertise, Formation et Support
>



--
Cédric Villemain               2ndQuadrant
http://2ndQuadrant.fr/     PostgreSQL : Expertise, Formation et Support