On 2009.09.18 at 15h32, concerning "Re: [SMS] DB2 Table/IndexSpace managed placement vs. StorClas MSR attributes", Terry Traylor <ter...tra...@schw...com> wrote to IBM-Main :
> Being as small shop you probably have one disk subsystem and one drive > type for your production environment, so the drives will all perform > the same no matter what storage class attributes are assigned. Terry : ah... I think I see one flaw (of many to come?) in my thinking. The MSR values will not include the queueing time related to UCB contention as observed by the end 'job' but only the actual device response. As you mentioned, that should be the same since all drives are in the same DMX1000 box and running through the same cache space. (told you we're small *grin*) That will be one of my research items - the comparison of response times - so we can see if the change is effective or not. > However, dataset striping can help, but you have to be selective about > what datasets you strip. [snip] 's been a while since I read the details but I thought I recalled that striping is mostly aimed/useful for sequential access. right? (I'll pursue that as well.) PAV was rejected here because we were required to license for the entire box capacity while half was for the 'Open Systems' side. Wasted money since we weren't using SMS for any DB2 environments at that time. Likely to still be rejected since approx. 5 volumes are affected. ----------> signature = 6 lines follows <-------------- Neil Duffee, Joe SysProg, U d'Ottawa, Ottawa, Ont, Canada telephone:1 613 562 5800 x4585 fax:1 613 562 5161 mailto:NDuffee of uOttawa.ca http:/ /aix1.uottawa.ca/ ~nduffee "How *do* you plan for something like that?" Guardian Bob, Reboot "For every action, there is an equal and opposite criticism." "Systems Programming: Guilty, until proven innocent" John Norgauer 2004 ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
