IBM Mainframe Discussion List <[email protected]> wrote on 02/09/2006 11:52:03 AM:
> > > > And does this mean another hoary old ROT - don't assign non-page datasets > > on page volumes - can be assigned to the dustbin of history ???. > On PAV-capable disks, that ROT was already trashed. ASM forces the > assignment of n aliases to a volume with n page datasets, so that it > could have n-suspended ASM paging I/Os (one per page ds) and one > exposure left for I/O to non-page datasets. > > Even with suspended I/Os eliminated for ASM, I presume it will still > assign the aliases so that it can usually have an idle exposures to do > its paging I/O. That is correct. For PAV DASD, ASM builds an environment to allow it to have up to 2 concurrently active channel programs for each data set. When a single page read is required to satisfy a page fault and ASM already has an active channel program to the data set, ASM starts another channel program to do the single page read instead of tacking the request on to the running channel program, so that resolution of the page fault is not delayed by adding it to the end of a long string of writes (for steal or swapout) or a long string of reads (for swap-in). Jim Mulder z/OS System Test IBM Corp. Poughkeepsie, NY ---------------------------------------------------------------------- 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
