Perhaps this presentation can help you:
| Abraços / Regards / Saludos,
Anderson Nobre Power and Storage Consultant IBM Systems Hardware Client Technical Team – IBM Systems Lab Services |
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| Phone: 55-19-2132-4317 E-mail: [email protected] | ||
----- Original message -----
From: Jim Doherty <[email protected]>
Sent by: [email protected]
To: gpfsug main discussion list <[email protected]>
Cc:
Subject: [EXTERNAL] Re: [gpfsug-discuss] advanced filecache math
Date: Thu, May 9, 2019 6:08 PM
A couple of observations on memory, a maxFilesToCache object takes anwhere from 6-10K, so 1 million =~ 6-10 Gig. Memory utilized in the mmfsd comes from either the pagepool, the shared memory segment used by MFTC objects, the token memory segment used to track MFTC objects, and newer is memory used by AFM. If the memory resources are in the mmfsd address space then this will show in the RSS size of the mmfsd. Ignore the VMM size, since the glibc change awhile back to allocate a heap for each thread VMM has become an imaginary number for a large multi-threaded application.There have been some memory leaks fixed in Ganesha that will be in 4.2.3 PTF15 which is available on fixcentralJim DohertyOn Thursday, May 9, 2019, 1:25:03 PM EDT, Sven Oehme <[email protected]> wrote:Unfortunate more complicated :)The consumption here is an estimate based on 512b inodes, which no newly created filesystem has as all new default to 4k. So if you have 4k inodes you could easily need 2x of the estimated value.Then there are extended attributes, also not added here, etc .So don't take this number as usage, it's really just a rough estimate.SvenOn Thu, May 9, 2019, 5:53 PM Achim Rehor <[email protected]> wrote:Sorry for my fast ( and not well thought) answer, before. You obviously are correct, there is no relation between the setting of maxFilesToCache, and the
fileCacheMem 38359956 k = 11718554 * 3352 bytes (inode size 512 + 2840)
usage. it is rather a statement of how many metadata may fit in the remaining structures outside the pagepool. this value does not change at all, when you modify your mFtC setting.
There is a really good presentation by Tomer Perry on the User Group meetings, referring about memory footprint of GPFS under various conditions.
In your case, you may very well hit the CES nodes memleak you just pointed out.
Sorry for my hasty reply earlier ;)
Achim
From: Stijn De Weirdt <[email protected]>
To: [email protected]
Date: 09/05/2019 16:48
Subject: Re: [gpfsug-discuss] advanced filecache math
Sent by: [email protected]
seems like we are suffering from
http://www-01.ibm.com/support/docview.wss?uid=isg1IJ12737
as these are ces nodes, we susepcted something wrong the caches, but it
looks like a memleak instead.
sorry for the noise (as usual you find the solution right after sending
the mail ;)
stijn
On 5/9/19 4:38 PM, Stijn De Weirdt wrote:
> hi achim,
>
>> you just misinterpreted the term fileCacheLimit.
>> This is not in byte, but specifies the maxFilesToCache setting :
> i understand that, but how does the fileCacheLimit relate to the
> fileCacheMem number?
>
>
>
> (we have a 32GB pagepool, and mmfsd is using 80GB RES (101 VIRT), so we
> are looking for large numbers that might explain wtf is going on
> (pardon my french ;)
>
> stijn
>
>>
>> UMALLOC limits:
>> bufferDescLimit 40000 desired 40000
>> fileCacheLimit 4000 desired 4000 <=== mFtC
>> statCacheLimit 1000 desired 1000 <=== mSC
>> diskAddrBuffLimit 200 desired 200
>>
>> # mmfsadm dump config | grep -E "maxFilesToCache|maxStatCache"
>> maxFilesToCache 4000
>> maxStatCache 1000
>>
>> Mit freundlichen Grüßen / Kind regards
>>
>> *Achim Rehor*
>>
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>>
>> From: Stijn De Weirdt <[email protected]>
>> To: gpfsug main discussion list <[email protected]>
>> Date: 09/05/2019 16:21
>> Subject: [gpfsug-discuss] advanced filecache math
>> Sent by: [email protected]
>>
>> --------------------------------------------------------------------------------
>>
>>
>>
>> hi all,
>>
>> we are looking into some memory issues with gpfs 5.0.2.2, and found
>> following in mmfsadm dump fs:
>>
>> > fileCacheLimit 1000000 desired 1000000
>> ...
>> > fileCacheMem 38359956 k = 11718554 * 3352 bytes (inode size 512 + 2840)
>>
>> the limit is 1M (we configured that), however, the fileCacheMem mentions
>> 11.7M?
>>
>> this is also reported right after a mmshutdown/startup.
>>
>> how do these 2 relate (again?)?
>>
>> mnay thanks,
>>
>> stijn
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>>
>>
>>
>>
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