Our environment is a single z9-BC mainframe (2096-R07(I01)), z/OS V1R9 @ RSU0906, a 3592-C06 tape controller w/2 FX4 channels, and 3592-E05 (TS1120) tape drives.
We're performing initial testing towards migrating to current tape hardware from (please don't ask, too embarrassed to tell). Using DFHSM (with DFDSS as the data mover) to back up a single 18GB sequential file (non compressed) to dual TS1120 tape drives is consuming over 50% of the total CPU. Looking at the FICON performance numbers while this is happening, I see huge (25% to 40%) utilization numbers for the 2 FX4 CHPIDS driving the tape controller, while the 2 FX4 CHPIDS connected to the DASD array are running only about 5% utilization apiece. 50% of our CPU seems (to me, anyway) to be a high price to pay to back up a single sequential file. I'm looking for (any or all of these): similar experiences, is this normal or whacked out, any tuning or performance tips that might help, how to determine exactly where the overhead is coming from, and (last but not least) how to approach IBM to address this issue. All constructive comments, questions and suggestions appreciated. Thanks. -Mike ---------------------------------------------------------------------- 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
