[gpfsug-discuss] Clarification about blocksize in stardanrd gpfs and GNR

Sven Oehme oehmes at gmail.com
Fri Mar 22 13:44:21 GMT 2019


Hi,

 

They are slightly different versions of the same tool. You should use gpfsperf as this is the one pre-packaged with newer versions of Scale. 

 

Sven

 

 

From: <gpfsug-discuss-bounces at spectrumscale.org> on behalf of "Dorigo Alvise (PSI)" <alvise.dorigo at psi.ch>
Reply-To: gpfsug main discussion list <gpfsug-discuss at spectrumscale.org>
Date: Friday, March 22, 2019 at 2:18 AM
To: gpfsug main discussion list <gpfsug-discuss at spectrumscale.org>
Subject: Re: [gpfsug-discuss] Clarification about blocksize in stardanrd gpfs and GNR

 

Thank you all guys for the answers. Just a quick question: what is the difference between gpfsperf and tsqosperf ? I knew the former, but not the latter (mentioned in your presentation). Do they do I/O test in different ways ?

 

thanks,

 

   Alvise

From: gpfsug-discuss-bounces at spectrumscale.org [gpfsug-discuss-bounces at spectrumscale.org] on behalf of Sven Oehme [oehmes at gmail.com]
Sent: Thursday, March 21, 2019 6:35 PM
To: gpfsug main discussion list
Subject: Re: [gpfsug-discuss] Clarification about blocksize in stardanrd gpfs and GNR

Lots of details in a presentation I did last year before I left IBM à http://files.gpfsug.org/presentations/2018/Singapore/Sven_Oehme_ESS_in_CORAL_project_update.pdf

 

Sven

 

From: <gpfsug-discuss-bounces at spectrumscale.org> on behalf of Daniel Kidger <daniel.kidger at uk.ibm.com>
Reply-To: gpfsug main discussion list <gpfsug-discuss at spectrumscale.org>
Date: Thursday, March 21, 2019 at 10:15 AM
To: <gpfsug-discuss at spectrumscale.org>
Cc: <gpfsug-discuss at spectrumscale.org>
Subject: Re: [gpfsug-discuss] Clarification about blocksize in stardanrd gpfs and GNR

 

Alvise,

 

Also note that that DeveloperWorks page was maintained by Scott Faddon. He has since left IBM and that page has unfortunately not been updated for almost 2 years. :-(

 

This page predates the current version 5.x of SpectrumScale which has been available since the beginning of 2018.

 

In version 5.x. the statement that there are 32 sub-blocks in one block is no longer true.

Now, by default you get a 4MiB Filesystem blocksize that has 512 sub0clocks, each 8192 bytes long.

Daniel

 

_________________________________________________________
Daniel Kidger

IBM Technical Sales Specialist

Spectrum Scale, Spectrum NAS and IBM Cloud Object Store

+44-(0)7818 522 266 
daniel.kidger at uk.ibm.com 

 

 

 

----- Original message -----
From: david_johnson at brown.edu
Sent by: gpfsug-discuss-bounces at spectrumscale.org
To: gpfsug main discussion list <gpfsug-discuss at spectrumscale.org>
Cc:
Subject: Re: [gpfsug-discuss] Clarification about blocksize in stardanrd gpfs and GNR
Date: Thu, Mar 21, 2019 1:32 PM
 
The underlying device in this context is the NSD, network storage device. This has relation at all to 512 byte or 4K disk blocks. Usually around a meg, always a power of two. 
  

  -- ddj 

Dave Johnson


On Mar 21, 2019, at 9:22 AM, Dorigo Alvise (PSI) <alvise.dorigo at psi.ch> wrote:
 

Hi,

I'm a little bit puzzled about different meanings of blocksize for different GPFS installation (standard and gnr).

 

>From this page https://www.ibm.com/developerworks/community/wikis/home?lang=en#!/wiki/General%20Parallel%20File%20System%20(GPFS)/page/File%20System%20Planning

 

I read:

·         The blocksize is the largest size IO that GPFS can issue to the underlying device

·         A subblock is 1/32nd of blocksize. This is the smallest allocation to a single file

For non-gnr GPFS device is quite clear to me (I hope): it is a single spinning disk (or ssd). And I verified this on a small cluster composed of nsd using their local hard drive.

 

Can someone explain what is the "device" in the case of GNR ? a single pdisk ?

 

Thanks,

 

  Alvise 

 

_______________________________________________
gpfsug-discuss mailing list
gpfsug-discuss at 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

 

Unless stated otherwise above:
IBM United Kingdom Limited - Registered in England and Wales with number 741598. 
Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU

_______________________________________________ gpfsug-discuss mailing list gpfsug-discuss at 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 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://gpfsug.org/pipermail/gpfsug-discuss_gpfsug.org/attachments/20190322/7d8bc6b5/attachment.htm>


More information about the gpfsug-discuss mailing list