Mark, Which is why in an earlier post I mentioned a dedicated LCU for Page datasets. That way you can always have an over abundance of Alias.
BTW I'm not saying that one should mindlessly go out and treat paging as just another dataset. I just don't like seeing a practice perpetuated when the reason for it has gone away. I was taught that Page Datasets are on dedicated volumes so that IO to another dataset would not cause the suspended channel program from ending. All the other discussion is about managing and mitigating contention. If the suggestion that page dataset isolation is absolutely critical, then why not give them a dedicated Cache Partition and FlashAccess as well? With 512GB of cache it would be easy to carve out 32GB and go back to a solid state paging environment :-) Ron > -----Original Message----- > From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On > Behalf Of Mark Zelden > Sent: Thursday, May 08, 2008 10:05 AM > To: IBM-MAIN@BAMA.UA.EDU > Subject: Re: [IBM-MAIN] 3 Page Datasets on one Volume > > On Thu, 8 May 2008 09:35:01 -0700, Ron Hawkins > <[EMAIL PROTECTED]> wrote: > > >Bill, > > > >The devil is in the detail. If the page datasets are being accessed > their > >own alias UCB then the channel commands, FCP frames and disk IO are > being > >interleaved with all the other volumes that share the same channels, > storage > >ports and disk drives. > > > >Even a heavy use sequential use dataset on the same volume will create > the > >same interference as if it was on another volume sharing the same > channels > >and Parity Group. In your example, I don't see how isolation reduces > that > >impact. > > > >Ron > > > > Ron, see my previous post and I'm sure there is something in the > archives > from either Jim Mulder or Peter Relson (where do ya think I got my > information > from?) :-) The other I/O could take the PAVs that ASM has > recommended > to WLM to assign. That could mean no UCB for a page request. > > http://bama.ua.edu/cgi-bin/wa?A2=ind0805&L=ibm- > main&D=1&O=D&T=0&P=49572 > > So while having multiple page data sets per volume should not be a > problem > with dynamic PAV, having other active data sets could be. > > Mark > -- > Mark Zelden > Sr. Software and Systems Architect - z/OS Team Lead > Zurich North America / Farmers Insurance Group - ZFUS G-ITO > mailto:[EMAIL PROTECTED] > z/OS Systems Programming expert at > http://expertanswercenter.techtarget.com/ > Mark's MVS Utilities: http://home.flash.net/~mzelden/mvsutil.html > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO > Search the archives at http://bama.ua.edu/archives/ibm-main.html ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
