<font size=2 face="sans-serif">Hello Bob,</font>
<br>
<br><font size=2 face="sans-serif">Right. Within some observation
interval, bytes read by an application will be reflected in gpfs_is_bytes_read,
regardless of how the byte values were obtained (by reading from "disk",
fetching from pagepool, or fetching from LROC). gpfs_ns_bytes_read
is only going to reflect bytes read from "disk" within that observation
interval.</font>
<br>
<br><font size=2 face="sans-serif">"mmdiag --lroc" provides some
LROC stats. There is also a GPFSLROC sensor; it does not appear to
be documented at this point, so I hope I haven't spoken out of turn.</font>
<br>
<br><font size=2 face="sans-serif">Eric Agar</font>
<br>
<br><font size=2 face="sans-serif">Regards, The Spectrum Scale (GPFS) team<br>
<br>
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<br><font size=1 color=#5f5f5f face="sans-serif">From:
</font><font size=1 face="sans-serif">"Oesterlin, Robert"
<Robert.Oesterlin@nuance.com></font>
<br><font size=1 color=#5f5f5f face="sans-serif">To:
</font><font size=1 face="sans-serif">gpfsug main discussion
list <gpfsug-discuss@spectrumscale.org></font>
<br><font size=1 color=#5f5f5f face="sans-serif">Cc:
</font><font size=1 face="sans-serif">"scale@us.ibm.com"
<scale@us.ibm.com></font>
<br><font size=1 color=#5f5f5f face="sans-serif">Date:
</font><font size=1 face="sans-serif">06/12/2017 06:50 PM</font>
<br><font size=1 color=#5f5f5f face="sans-serif">Subject:
</font><font size=1 face="sans-serif">Re: Meaning
of API Stats Category</font>
<br>
<hr noshade>
<br>
<br>
<br><font size=2 face="Calibri">Can you tell me how LROC plays into this?
I\u2019m trying to understand if the difference between gpfs_ns_bytes_read
and gpfs_is_bytes_read on a cluster-wide basis reflects the amount of data
that is recalled from pagepool+LROC (assuming the majority of the nodes
have LROC.</font>
<br><font size=2 face="Calibri"> </font>
<br><font size=2 face="Calibri">Any insight on LROC stats would helpful
as well.</font>
<br><font size=2 face="Calibri"> </font>
<br><img src=cid:_4_0F423DA00F423B3400049D408525813F style="border:0px solid;">
<br><font size=2 face="Calibri"> </font>
<br><font size=2 face="Calibri">Bob Oesterlin<br>
Sr Principal Storage Engineer, Nuance<br>
507-269-0413</font>
<br><font size=3 face="Times New Roman"> </font>
<br><font size=2 face="Calibri"> </font>
<br><font size=2 face="Calibri"> </font>
<br><font size=3 face="Calibri"><b>From: </b><gpfsug-discuss-bounces@spectrumscale.org>
on behalf of IBM Spectrum Scale <scale@us.ibm.com><b><br>
Reply-To: </b>gpfsug main discussion list <gpfsug-discuss@spectrumscale.org><b><br>
Date: </b>Monday, June 12, 2017 at 4:01 PM<b><br>
To: </b>gpfsug main discussion list <gpfsug-discuss@spectrumscale.org><b><br>
Subject: </b>[EXTERNAL] Re: [gpfsug-discuss] Meaning of API Stats Category</font>
<br><font size=2 face="Calibri"> </font>
<br><font size=2 face="sans-serif">Hello Kristy,</font><font size=2 face="Calibri">
<br>
</font><font size=2 face="sans-serif"><br>
The GPFSFileSystemAPI and GPFSNodeAPI sensor metrics are from the point
of view of "applications" in the sense that they provide stats
about I/O requests made to files in GPFS file systems from user level applications
using POSIX interfaces like open(), close(), read(), write(), etc.</font><font size=2 face="Calibri">
<br>
</font><font size=2 face="sans-serif"><br>
This is in contrast to similarly named sensors without the "API"
suffix, like GPFSFilesystem and GPFSNode. Those sensors provide stats
about I/O requests made by the GPFS code to NSDs (disks) making up GPFS
file systems.</font><font size=2 face="Calibri"> <br>
</font><font size=2 face="sans-serif"><br>
The relationship between application I/O and disk I/O might or might not
be obvious. Consider some examples. An application that starts
sequentially reading a file might, at least initially, cause more disk
I/O than expected because GPFS has decided to prefetch data. An application
write() might not immediately cause a the writing of disk blocks due to
the operation of the pagepool. Ultimately, application write()s might
cause twice as much data written to disk due to the replication factor
of the file system. Application I/O concerns itself with user data;
disk I/O might have to occur to handle the user data and associated file
system metadata (like inodes and indirect blocks).</font><font size=2 face="Calibri">
<br>
</font><font size=2 face="sans-serif"><br>
The difference between GPFSFileSystemAPI and GPFSNodeAPI: GPFSFileSystemAPI
reports stats for application I/O per filesystem per node; GPFSNodeAPI
reports application I/O stats per node. Similarly, GPFSFilesystem
reports stats for disk I/O per filesystem per node; GPFSNode reports disk
I/O stats per node.</font><font size=2 face="Calibri"> <br>
</font><font size=2 face="sans-serif"><br>
I hope this helps.</font><font size=2 face="Calibri"> </font><font size=2 face="sans-serif"><br>
Eric Agar</font><font size=2 face="Calibri"> <br>
<br>
</font><font size=2 face="sans-serif"><br>
Regards, The Spectrum Scale (GPFS) team<br>
<br>
------------------------------------------------------------------------------------------------------------------<br>
If you feel that your question can benefit other users of Spectrum
Scale (GPFS), then please post it to the public IBM developerWroks Forum
at </font><a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__www.ibm.com_developerworks_community_forums_html_forum-3Fid-3D11111111-2D0000-2D0000-2D0000-2D000000000479&d=DwMGaQ&c=djjh8EKwHtOepW4Bjau0lKhLlu-DxM1dlgP0rrLsOzY&r=LPDewt1Z4o9eKc86MXmhqX-45Cz1yz1ylYELF9olLKU&m=5sAByjnB2P9tv298gm9m1cJjOe9Sjm2TqyQYw-vXIDo&s=AkUR-geA0jejuYEiraffUNtNEXHMtZG6k-r-k1lEwpU&e="><font size=2 color=blue face="sans-serif"><u>https://www.ibm.com/developerworks/community/forums/html/forum?id=11111111-0000-0000-0000-000000000479</u></font></a><font size=2 face="sans-serif">.
<br>
<br>
If your query concerns a potential software error in Spectrum Scale (GPFS)
and you have an IBM software maintenance contract please contact 1-800-237-5511
in the United States or your local IBM Service Center in other countries.
<br>
<br>
The forum is informally monitored as time permits and should not be used
for priority messages to the Spectrum Scale (GPFS) team.</font><font size=2 face="Calibri">
<br>
<br>
<br>
</font><font size=1 color=#5f5f5f face="sans-serif"><br>
From: </font><font size=1 face="sans-serif">"Oesterlin,
Robert" <Robert.Oesterlin@nuance.com></font><font size=2 face="Calibri">
</font><font size=1 color=#5f5f5f face="sans-serif"><br>
To: </font><font size=1 face="sans-serif">gpfsug
main discussion list <gpfsug-discuss@spectrumscale.org></font><font size=2 face="Calibri">
</font><font size=1 color=#5f5f5f face="sans-serif"><br>
Date: </font><font size=1 face="sans-serif">06/12/2017
04:43 PM</font><font size=2 face="Calibri"> </font><font size=1 color=#5f5f5f face="sans-serif"><br>
Subject: </font><font size=1 face="sans-serif">Re:
[gpfsug-discuss] Meaning of API Stats Category</font><font size=2 face="Calibri">
</font><font size=1 color=#5f5f5f face="sans-serif"><br>
Sent by: </font><font size=1 face="sans-serif">gpfsug-discuss-bounces@spectrumscale.org</font><font size=2 face="Calibri">
</font>
<div align=center>
<hr noshade></div>
<br><font size=2 face="Calibri"><br>
<br>
</font><font size=2 face="Calibri"><br>
Hi Kristy</font><font size=2 face="Calibri"> </font><font size=2 face="Calibri"><br>
</font><font size=2 face="Calibri"> </font><font size=2 face="Calibri"><br>
What I *think* the difference is:</font><font size=2 face="Calibri"> </font><font size=2 face="Calibri"><br>
</font><font size=2 face="Calibri"> </font><font size=2 face="Calibri"><br>
gpfs_fis: - calls to the GPFS file system interface</font><font size=2 face="Calibri">
</font><font size=2 face="Calibri"><br>
gpfs_fs: calls from the node that actually make it to the NSD server/metadata</font><font size=2 face="Calibri">
</font><font size=2 face="Calibri"><br>
</font><font size=2 face="Calibri"> </font><font size=2 face="Calibri"><br>
The difference being what\u2019s served out of the local node pagepool.</font><font size=2 face="Calibri">
</font><font size=2 face="Calibri"><br>
</font><font size=2 face="Calibri"> </font><font size=2 face="Calibri"><br>
Bob Oesterlin<br>
Sr Principal Storage Engineer, Nuance</font><font size=2 face="Calibri"><br>
</font><font size=2 face="Calibri"><br>
</font><font size=2 face="Calibri"> </font><font size=3 face="Calibri"><b><br>
From: </b><gpfsug-discuss-bounces@spectrumscale.org> on behalf of
Kristy Kallback-Rose <kkr@lbl.gov><b><br>
Reply-To: </b>gpfsug main discussion list <gpfsug-discuss@spectrumscale.org><b><br>
Date: </b>Monday, June 12, 2017 at 3:17 PM<b><br>
To: </b>gpfsug main discussion list <gpfsug-discuss@spectrumscale.org><b><br>
Subject: </b>[EXTERNAL] [gpfsug-discuss] Meaning of API Stats Category</font><font size=2 face="Calibri">
</font><font size=2 face="Calibri"><br>
</font><font size=2 face="Calibri"> </font><font size=2 face="Calibri"><br>
Hi, <br>
</font><font size=2 face="Calibri"> </font><font size=2 face="Calibri"><br>
Can anyone provide more detail about what is meant by the following
two categories of stats? The PDG has a limited description as far as I
could see. I'm not sure what is meant by Application PoV. Would the Grafana
bridge count as an "application"?</font><font size=2 face="Calibri">
</font><font size=2 face="Calibri"><br>
</font><font size=2 face="Calibri"> </font><font size=2 face="Calibri"><br>
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