Fifty percent savings in residence time are likely to be reflections of larger block sizes, asynchronous, overlapped I/O operations (possible, even easy, with BSAM), or both.
Some measurements would be in order. John Gilmore, Ashland, MA 01721 - USA On 8/17/12, Dana Mitchell <mitchd...@gmail.com> wrote: > Thus far we have 1.13 installed on systems at our DR site. The bulk of the > daily work that goes on on these systems, is DFDSS restore from full volume > disk backup datsets that are FTP'ed to that site and we have observed these > restore jobs running in about 50% less wall clock time than before the > upgrade. Could the change from EXCP to BSAM account for this also? > > Dana > > > > On Thu, 16 Aug 2012 17:42:29 -0500, Steve Thompson <sthomp...@us.ibm.com> > wrote: > >>__________________ >> >>We have seen massive savings - primarily in wall-clock savings - but from >>what I understand (2nd and 3rd hand): >> >>3490s have a max blksize of 64k; 3590s have a max blksize of 256K >>If you use virtual tapes - make sure the virtual tapes are defined as >>3590s to get the best LBI benefit >> >><SNIPPAGE> >> >>Please forgive me but I am having issues with my email system, so headers >>got lost. >> >>At any rate, at 1.12 the DEVTYPE (I think that was the macro) gets updated >>to allow 3490s to go LBI at 256K blocks. >> >>If you are running Connect:Direct for z/OS, you will need the equivalent >>PTF. >> >>Certain ISV software may not handle the change from 65K max blksize for >>the 3490s. >> >>Be careful if you are going to have one system at 1.12 (or greater) and >>another system below 1.12, because you will run into problems with the >>lower system reading the tapes. >> >>There are exits for the 1.12 level in handling this. Look at the ADRDSSU >>manuals with regards to those exits. >> >>Regards, >>Steve Thompson >>Connect:Direct for z/OS >>IBM -- Irving TX Lab >> >>---------------------------------------------------------------------- >>For IBM-MAIN subscribe / signoff / archive access instructions, >>send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
