So your saying maxStatCache should be raised on LROC enabled nodes only as its the only place under Linux its used and should be set low on non-LROC enabled nodes.
Fine just good to know, nice and easy now with nodeclasses.... Peter Childs ________________________________________ From: [email protected] <[email protected]> on behalf of Sven Oehme <[email protected]> Sent: Wednesday, December 21, 2016 11:37:46 AM To: gpfsug main discussion list Subject: Re: [gpfsug-discuss] LROC StatCache is not useful on Linux, that hasn't changed if you don't use LROC on the same node. LROC uses the compact object (StatCache) to store its pointer to the full file Object which is stored on the LROC device. so on a call for attributes that are not in the StatCache the object gets recalled from LROC and converted back into a full File Object, which is why you still need to have a reasonable maxFiles setting even you use LROC as you otherwise constantly move file infos in and out of LROC and put the device under heavy load. sven On Wed, Dec 21, 2016 at 12:29 PM Peter Childs <[email protected]<mailto:[email protected]>> wrote: My understanding was the maxStatCache was only used on AIX and should be set low on Linux, as raising it did't help and wasted resources. Are we saying that LROC now uses it and setting it low if you raise maxFilesToCache under linux is no longer the advice. Peter Childs ________________________________________ From: [email protected]<mailto:[email protected]> <[email protected]<mailto:[email protected]>> on behalf of Sven Oehme <[email protected]<mailto:[email protected]>> Sent: Wednesday, December 21, 2016 9:23:16 AM To: gpfsug main discussion list Subject: Re: [gpfsug-discuss] LROC Lroc only needs a StatCache object as it 'compacts' a full open File object (maxFilesToCache) to a StatCache Object when it moves the content to the LROC device. therefore the only thing you really need to increase is maxStatCache on the LROC node, but you still need maxFiles Objects, so leave that untouched and just increas maxStat Olaf's comment is important you need to make sure your manager nodes have enough memory to hold tokens for all the objects you want to cache, but if the memory is there and you have enough its well worth spend a lot of memory on it and bump maxStatCache to a high number. i have tested maxStatCache up to 16 million at some point per node, but if nodes with this large amount of inodes crash or you try to shut them down you have some delays , therefore i suggest you stay within a 1 or 2 million per node and see how well it does and also if you get a significant gain. i did help Bob to setup some monitoring for it so he can actually get comparable stats, i suggest you setup Zimon and enable the Lroc sensors to have real stats too , so you can see what benefits you get. Sven On Tue, Dec 20, 2016 at 8:13 PM Matt Weil <[email protected]<mailto:[email protected]><mailto:[email protected]<mailto:[email protected]>>> wrote: as many as possible and both have maxFilesToCache 128000 and maxStatCache 40000 do these effect what sits on the LROC as well? Are those to small? 1million seemed excessive. On 12/20/16 11:03 AM, Sven Oehme wrote: how much files do you want to cache ? and do you only want to cache metadata or also data associated to the files ? sven On Tue, Dec 20, 2016 at 5:35 PM Matt Weil <[email protected]<mailto:[email protected]><mailto:[email protected]<mailto:[email protected]>>> wrote: https://www.ibm.com/developerworks/community/wikis/home?lang=en#!/wiki/General%20Parallel%20File%20System%20(GPFS)/page/Flash%20Storage<https://www.ibm.com/developerworks/community/wikis/home?lang=en#%21/wiki/General%20Parallel%20File%20System%20%28GPFS%29/page/Flash%20Storage> Hello all, Are there any tuning recommendations to get these to cache more metadata? Thanks Matt _______________________________________________ gpfsug-discuss mailing list gpfsug-discuss at spectrumscale.org<http://spectrumscale.org><http://spectrumscale.org> http://gpfsug.org/mailman/listinfo/gpfsug-discuss _______________________________________________ gpfsug-discuss mailing list gpfsug-discuss at spectrumscale.org<http://spectrumscale.org><http://spectrumscale.org> http://gpfsug.org/mailman/listinfo/gpfsug-discuss _______________________________________________ gpfsug-discuss mailing list gpfsug-discuss at spectrumscale.org<http://spectrumscale.org><http://spectrumscale.org> http://gpfsug.org/mailman/listinfo/gpfsug-discuss _______________________________________________ gpfsug-discuss mailing list gpfsug-discuss at spectrumscale.org<http://spectrumscale.org> http://gpfsug.org/mailman/listinfo/gpfsug-discuss _______________________________________________ gpfsug-discuss mailing list gpfsug-discuss at spectrumscale.org http://gpfsug.org/mailman/listinfo/gpfsug-discuss
