Thank you Eric. That did help. On Mon, Jun 12, 2017 at 2:01 PM, IBM Spectrum Scale <[email protected]> wrote:
> Hello Kristy, > > 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. > > 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. > > 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). > > 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. > > I hope this helps. > Eric Agar > > > Regards, The Spectrum Scale (GPFS) team > > ------------------------------------------------------------ > ------------------------------------------------------ > 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 > https://www.ibm.com/developerworks/community/ > forums/html/forum?id=11111111-0000-0000-0000-000000000479. > > 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 <(800)%20237-5511> in the United States or your local IBM > Service Center in other countries. > > The forum is informally monitored as time permits and should not be used > for priority messages to the Spectrum Scale (GPFS) team. > > > > From: "Oesterlin, Robert" <[email protected]> > To: gpfsug main discussion list <[email protected]> > Date: 06/12/2017 04:43 PM > Subject: Re: [gpfsug-discuss] Meaning of API Stats Category > Sent by: [email protected] > ------------------------------ > > > > Hi Kristy > > What I *think* the difference is: > > gpfs_fis: - calls to the GPFS file system interface > gpfs_fs: calls from the node that actually make it to the NSD > server/metadata > > The difference being what’s served out of the local node pagepool. > > Bob Oesterlin > Sr Principal Storage Engineer, Nuance > > > *From: *<[email protected]> on behalf of Kristy > Kallback-Rose <[email protected]> > * Reply-To: *gpfsug main discussion list <[email protected] > > > * Date: *Monday, June 12, 2017 at 3:17 PM > * To: *gpfsug main discussion list <[email protected]> > * Subject: *[EXTERNAL] [gpfsug-discuss] Meaning of API Stats Category > > Hi, > > 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"? > > _______________________________________________ > 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 > >
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