Sorry for my ignorance and naivete, but I am simply staggered at the volume of page volumes of whatever size, 100 - 240.
I have just a Dev Test z/VM environment with 2 measly 3390-3's for Paging. Granted, I am running only 5 z/OS vm's and 3 Linux vm's. But, what does someone have to run that needs 240 page volumes? I am sure it is justified, I would just like to know more about the workload. Mark Wheeler <mwheele...@hotmail.com> Sent by: The IBM z/VM Operating System <IBMVM@LISTSERV.UARK.EDU> 09/30/2010 09:00 AM Please respond to The IBM z/VM Operating System <IBMVM@LISTSERV.UARK.EDU> To IBMVM@LISTSERV.UARK.EDU cc Subject Re: Mixed page volume sizes Dennis, You should be fine mixing sizes so long as you watch utilizations of individual volumes (particularly the smallest ones) and don't let any of them go over 50% full. We ran out of 3390-9 volumes a while ago and had to start adding 3390-27's for paging. Since they're all virtualized inside the storage array, device response times are pretty much all the same. When the 3390-9's get toward 50% full (or the high-water mark hits the end of the device - another thing I like to watch), I add some more 3390-27's. I pretty much disregard the aggregate page volume utilization, which is often less than 20% in our case. Given that 240-248 puts you very close to the max number of page volumes, 3390-3's may not be the best choice because with a bit more growth, the only thing you'll be able to do is watch space utilization go beyond 50%, which won't be good. A place to start may be 120 3390-9's @ 33% util each. Then watch individual device response times to see if you need more actuators. Good luck! Mark Wheeler UnitedHealth Group -- "Excellence. Always. If Not Excellence, What? If Not Excellence Now, When?" Tom Peters, author of "The Little BIG Things" > Date: Wed, 29 Sep 2010 15:53:25 -0700 > From: dennis.l.o'br...@bankofamerica.com > Subject: Mixed page volume sizes > To: IBMVM@LISTSERV.UARK.EDU > > On of our z/VM 5.4.0 systems is about to grow to 140 GB of storage. Given our target overcommit ratio of 3:1, and IBM's advice to keep paging space no more than 50% full, this should just about fit onto 240 or 248 3390-3 sized volumes. My question is what will happen the next time we add storage. Clearly, we'll have to start using 3390-9 sized volumes for paging. Would we be better off converting only enough volumes to satisfy the space requirement, which would maximize the number of devices, or should we convert all volumes to 3390-9 to keep them the same size? My concern is that if we mix sizes, CP will try to allocate the same amount of space on each volume, and the 3390-3's will get more than half full. On the other hand, maximizing the number of devices maximizes the number of concurrent I/O's. Our Storage people aren't going to give me 240 3390-9's if I don't need them, so if I add another 32 GB of storage, my choice would be something like 212 3390-3's and 28 3390-9's, or 100 3390-9's. Which would be a better choice? > Dennis > > "Decision" is not a verb.
