Memory issue on RHEL 6.9

Prashant Shettar

Memory issue on RHEL 6.9

Hello Everyone,

  We are running multi partition database on RHEL 6.9. During heavy workload, database is running out of main memory and stops responding.  when I looked at the memory usage during the incident, memory used by db2 was much less.Cache memory used was the culprit. Cache memory increased to the level of main memory. 

I am suspecting some process is caching data too much. Can you please help me to track / check which filesystems or device  has filesystem cache enabled at the operating system level?  

 

 I am using db2 V9.7 fp6.

 

Regards

PS

Nadir Doctor

Memory issue on RHEL 6.9
(in response to Prashant Shettar)
Hi Prashant,

You can use db2look with the layout option to confirm if any tablespaces
are using filesystems with caching turned on - note that those containing
lob's which aren't inlined will need caching to be on.

Sample command: db2look -d <db_name> -l -o <output_file>


Best Regards,
Nadir


On Wed, Nov 15, 2017 at 5:50 AM, Prashant Shettar <[login to unmask email]>
wrote:

> Hello Everyone,
>
> We are running multi partition database on RHEL 6.9. During heavy
> workload, database is running out of main memory and stops responding.
> when I looked at the memory usage during the incident, memory used by db2
> was much less.Cache memory used was the culprit. Cache memory increased to
> the level of main memory.
>
> I am suspecting some process is caching data too much. Can you please help
> me to track / check which filesystems or device has filesystem cache
> enabled at the operating system level?
>
>
>
> I am using db2 V9.7 fp6.
>
>
>
> Regards
>
> PS
>
> -----End Original Message-----
>

Prashant Shettar

Memory issue on RHEL 6.9
(in response to Nadir Doctor)
Hello Nadir

None of the table spaces has file system cache On. I am suspecting
something to do with Raw devices attached to the server.

Regards
PS



On Wed 15. Nov 2017 at 15:23, Nadir Doctor <[login to unmask email]> wrote:

> Hi Prashant,
>
> You can use db2look with the layout option to confirm if any tablespaces
> are using filesystems with caching turned on - note that those containing
> lob's which aren't inlined will need caching to be on.
>
> Sample command: db2look -d <db_name> -l -o <output_file>
>
>
> Best Regards,
> Nadir
>
>
> On Wed, Nov 15, 2017 at 5:50 AM, Prashant Shettar <[login to unmask email]>
> wrote:
>
>> Hello Everyone,
>>
>> We are running multi partition database on RHEL 6.9. During heavy
>> workload, database is running out of main memory and stops responding.
>> when I looked at the memory usage during the incident, memory used by db2
>> was much less.Cache memory used was the culprit. Cache memory increased to
>> the level of main memory.
>>
>> I am suspecting some process is caching data too much. Can you please
>> help me to track / check which filesystems or device has filesystem cache
>> enabled at the operating system level?
>>
>>
>>
>> I am using db2 V9.7 fp6.
>>
>>
>>
>> Regards
>>
>> PS
>>
>> -----End Original Message-----
>