DMP is most likely throttling things back due to an issue on a path: I/O throttling is a mechanism by which Dynamic Multi-Pathing (DMP) temporarily stops issuing I/Os to paths that appear to be either overloaded or underperforming. There is a default I/O throttling mechanism in DMP based on the number of requests queued on a path.
I am researching why you are seeing differing partition sizes. Would think it has something to do with configuration within the OS level or vxvm area, not the array itself. Regards, Terrie Douglas Sr. Prin. Technical Support Engineer Symantec Software Corporation Email: [email protected] Customer Support: 1(800) 342-0652 View your case online at: https://mysupport.symantec.com Save time and visit the Veritas Installation Assessment Services website and check out our automated tools: https://vias.symantec.com/main.php "This message (including any attachments) is intended only for the use of the individual or entity to which it is addressed and may contain information that is non-public,proprietary, privileged, confidential, and exempt from disclosure under applicable law or may constitute as attorney work product. If you are not the intended recipient, you are hereby notified that any use, dissemination, distribution, or copying of this communication is strictly prohibited. If you have received this communication in error,notify us immediately by telephone and (i) destroy this message if a facsimile or (ii) delete this message immediately if this is an electronic communication." -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Thursday, July 26, 2012 8:56 AM To: William Havey Cc: [email protected] Subject: Re: [Veritas-vx] Question over DMP partitionsize Hi William, Thanks for the reply. Not sure how to get this track cach size? What's confusing me most here is that the values are so different between the two arrays. They're identical models set-up up the same and with the same number of disks allocated to the servers - sorry, forgot to mention they're in an HA pair using VCS. The only difference is that IBM_SHARK0 is local to the server where the workload is currently running, and IBM_SHARK1 is in another building about 1.5KM's away. It's this disparity that is confusing me and making me wonder whether an issue we are seeing is being caused by this, or if it's an indication of an issue, though I've been informed by our storage people that there's nothing wrong with either array. This is certainly not something we've changed so I don't know if VxVM/DMP is throttling things back because it's seeing an issue. I have seen messages in the /etc/vx/dmpevents.log file for disks in the IBM_SHARK1 array reporting 'Throttled Path' and then 'Un-throttled Path' and I'm trying to work out if the two are linked. Cheers Phil. Veritas-vx maillist - [email protected] http://mailman.eng.auburn.edu/mailman/listinfo/veritas-vx _______________________________________________ Veritas-vx maillist - [email protected] http://mailman.eng.auburn.edu/mailman/listinfo/veritas-vx
