[gpfsug-discuss] LROC

Keigo Matsubara MKEIGO at jp.ibm.com
Tue Dec 20 23:25:41 GMT 2016


I still see the following statement* regarding with the use of LROC in FAQ 
(URL #1).
Are there any issues anticipated to use LROC on protocol nodes?

Q8.3: What are some configuration considerations when deploying the 
protocol functionality?
A8.3: Configuration considerations include:
    (... many lines are snipped ...)
Several GPFS configuration aspects have not been explicitly tested with 
the protocol function:
    (... many lines are snipped ...)
Local Read Only Cache*
    (... many lines are snipped ...)

Q2.25: What are the current requirements when using local read-only cache?
A2.25: The current requirements/limitations for using local read-only 
cache include:
- A minimum of IBM Spectrum Scale V4.1.0.1.
- Local read-only cache is only supported on Linux x86 and Power.
- The minimum size of a local read-only cache device is 4 GB.
- The local read-only cache requires memory equal to 1% of the local 
read-only device's capacity.
Note: Use of local read-only cache does not require a server license

[1] IBM Spectrum Scale™ Frequently Asked Questions and Answers (November 
2016)
https://www.ibm.com/support/knowledgecenter/STXKQY/gpfsclustersfaq.html

---
Keigo Matsubara, Industry Architect, IBM Japan
TEL: +81-50-3150-0595, T/L: 6205-0595




From:   "Olaf Weiser" <olaf.weiser at de.ibm.com>
To:     gpfsug main discussion list <gpfsug-discuss at spectrumscale.org>
Date:   2016/12/21 05:31
Subject:        Re: [gpfsug-discuss] LROC
Sent by:        gpfsug-discuss-bounces at spectrumscale.org



it's all true and right, but please have in mind.. with MFTC and the 
number of nodes  in the ( remote and local ) cluster, you 'll need token 
mem
since R42 token Mem is allocated automatically .. so the old tokenMEMLimit 
is more or less obsolete.. but you should have your overall configuration 
in mind, when raising MFTC clusterwide...

just a hint.. 

have fun...
Mit freundlichen Grüßen / Kind regards

 
Olaf Weiser

EMEA Storage Competence Center Mainz, German / IBM Systems, Storage 
Platform,
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IBM Deutschland
IBM Allee 1
71139 Ehningen
Phone: +49-170-579-44-66
E-Mail: olaf.weiser at de.ibm.com
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IBM Deutschland GmbH / Vorsitzender des Aufsichtsrats: Martin Jetter
Geschäftsführung: Martina Koederitz (Vorsitzende), Susanne Peter, Norbert 
Janzen, Dr. Christian Keller, Ivo Koerner, Markus Koerner
Sitz der Gesellschaft: Ehningen / Registergericht: Amtsgericht Stuttgart, 
HRB 14562 / WEEE-Reg.-Nr. DE 99369940 



From:        "Oesterlin, Robert" <Robert.Oesterlin at nuance.com>
To:        gpfsug main discussion list <gpfsug-discuss at spectrumscale.org>
Date:        12/20/2016 08:19 PM
Subject:        Re: [gpfsug-discuss] LROC
Sent by:        gpfsug-discuss-bounces at spectrumscale.org



We’re currently deploying LROC in many of our compute nodes – results so 
far have been excellent. We’re putting in 240gb SSDs, because we have 
mostly small files. As far as I know, the amount of inodes and directories 
in LROC are not limited, except by the size of the cache disk.
 
Look at these config options for LROC:
 
lrocData
Controls whether user data is populated into the local read-only cache. 
Other configuration options can be used to select the data that is 
eligible for the local read-only cache. When using more than one such 
configuration option, data that matches any of the specified criteria is 
eligible to be saved.
Valid values are yes or no. The default value is yes.
If lrocData is set to yes, by default the data that was not already in the 
cache when accessed by a user is subsequently saved to the local read-only 
cache. The default behavior can be overridden using thelrocDataMaxFileSize 
and lrocDataStubFileSizeconfiguration options to save all data from small 
files or all data from the initial portion of large files.
lrocDataMaxFileSize
Limits the data that may be saved in the local read-only cache to only the 
data from small files.
A value of -1 indicates that all data is eligible to be saved. A value of 
0 indicates that small files are not to be saved. A positive value 
indicates the maximum size of a file to be considered for the local 
read-only cache. For example, a value of 32768 indicates that files with 
32 KB of data or less are eligible to be saved in the local read-only 
cache. The default value is 0.
lrocDataStubFileSize
Limits the data that may be saved in the local read-only cache to only the 
data from the first portion of all files.
A value of -1 indicates that all file data is eligible to be saved. A 
value of 0 indicates that stub data is not eligible to be saved. A 
positive value indicates that the initial portion of each file that is 
eligible is to be saved. For example, a value of 32768 indicates that the 
first 32 KB of data from each file is eligible to be saved in the local 
read-only cache. The default value is 0.
lrocDirectories
Controls whether directory blocks is populated into the local read-only 
cache. The option also controls other file system metadata such as 
indirect blocks, symbolic links, and extended attribute overflow blocks.
Valid values are yes or no. The default value is yes.
lrocInodes
Controls whether inodes from open files is populated into the local 
read-only cache; the cache contains the full inode, including all disk 
pointers, extended attributes, and data.
Valid values are yes or no. The default value is yes.
 
 
Bob Oesterlin
Sr Principal Storage Engineer, Nuance
507-269-0413
 
 
 
From: <gpfsug-discuss-bounces at spectrumscale.org> on behalf of Matt Weil 
<mweil at wustl.edu>
Reply-To: gpfsug main discussion list <gpfsug-discuss at spectrumscale.org>
Date: Tuesday, December 20, 2016 at 1:13 PM
To: "gpfsug-discuss at spectrumscale.org" <gpfsug-discuss at spectrumscale.org>
Subject: [EXTERNAL] Re: [gpfsug-discuss] LROC
 
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 <mweil at wustl.edu> wrote:
https://www.ibm.com/developerworks/community/wikis/home?lang=en#!/wiki/General%20Parallel%20File%20System%20(GPFS)/page/Flash%20Storage


Hello all,

Are there any tuning recommendations to get these to cache more metadata?

Thanks

Matt

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