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 > > > The devil is in the details of the definition of "low to medium use." > If > such a data set is sequential and it is not used for days on end, when > it is > finally used it may easily be accessed hundreds of times per second for > however > long it takes to read or write the entire data set. If there is a need > for > high paging performance during this burst, then paging performance will > likely > suffer. There are several things that paging can do to get its I/O > request > ahead of others in the queue (e.g., use of the IOSXIMEX flag bit in the > IOSB), but I don't know if paging I/O does this. And paging I/O > interrupts are > processed ahead of other pending interrupts, I believe, thus allowing > the next > paging I/O to be started ahead of others. > > Bill Fairchild > Rocket Software > ---------------------------------------------------------------------- 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
