[gpfsug-discuss] QoS question

[Jan-Frode Myklebust]

XFS on Irix had a feature similar to QoS, called GRIO (guaranteed rate
I/O), where applications could reserve a given bandwidth.

http://www.sgistuff.net/software/irixintro/documents/xfs-whitepaper.html

Sounds somewhat similar to QoS, but focused on giving applications
guaranteed bandwidth, not iops.



-jf


ons. 15. jun. 2016 kl. 00.08 skrev Marc A Kaplan <makaplan at us.ibm.com>:

> Yes, in QOS for 4.2.0 there are some simple assumptions that may not make
> a lot of sense in some configurations, especially configurations with many
> (100s) of nodes mounting the same file system...    You can try out what
> you suggested and in 4.2.0 I think it will pretty much work as you suggest
> -- essentially you are allocating 466 maintenance iops to every node,
> knowing that most of those nodes will not be using their allocation of IOPS.
>
> In later releases, you may find that we will address some of these kinds
> of quirks in QOS.
>
> QOS is a new feature for GPFS, and I don't think you'll find anything like
> it in any commercial file system offering.  (Correct me with example(s) if
> I am wrong on this point.)
> So think of it as "release 1.0" (of QOS) and let us know how well it works
> for you and how it might be improved....
>
> --marc of Spectrum(GP)FS
>
>
>
> From:        "Buterbaugh, Kevin L" <Kevin.Buterbaugh at Vanderbilt.Edu>
> To:        gpfsug main discussion list <gpfsug-discuss at spectrumscale.org>
> Date:        06/14/2016 04:50 PM
> Subject:        [gpfsug-discuss] QoS question
> Sent by:        gpfsug-discuss-bounces at spectrumscale.org
> ------------------------------
>
>
>
> Hi All,
>
> We have recently upgraded to GPFS 4.2.0-3 and so I am getting ready to
> dive into my first attempts at using the new QoS features.  I want to make
> sure I am understanding the documentation:
>
> "The IOPS values that you set in an mmchqos command apply to all I/O
> operations that are issued by all the nodes that have the specified file
> system mounted. You should adjust your allocations of IOPS accordingly.
>
> For example, if you 600 IOPS to the maintenance class, and there are six
> nodes that have the file system mounted, then QoS allocates 100 IOPS to the
> maintenance class of each node. If you then run maintenance commands that
> affect only three of the nodes, the commands runs with an actual allocation
> of 300 IOPS, or 100 IOPS per node. To run maintenance commands that affect
> three nodes with an actual allotment of 600 IOPS, or 200 per node, allocate
> 1200 IOPS to the maintenanceclass. "
>
> We have a ~700 node cluster with 15 NSD servers.  Here’s how I interpret
> the above assuming that I have determined that I want to allow 7,000 IOPs …
> please correct me if I’m wrong...
>
> 7,000 IOPs / 700 nodes would be 10 IOPs per node.
>
> But I want those 7,000 IOPs to be divided amongst my 15 NSD servers that
> are going to be doing the maintenance (a restripe, for example), so 7,000 /
> 15 = 466.67.
>
> 466.67 * 700 (nodes in cluster) = 326,666.67.  So I would allocate 326,666
> IOPs to the maintenance class?
>
> Thanks in advance…
>
> Kevin
> —
> Kevin Buterbaugh - Senior System Administrator
> Vanderbilt University - Advanced Computing Center for Research and
> Education
>
> *Kevin.Buterbaugh at vanderbilt.edu* <Kevin.Buterbaugh at vanderbilt.edu>-
> (615)875-9633
>
>
>
>
> _______________________________________________
> 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/20160615/e2eb30f9/attachment-0002.htm>