Q1: I would argue that you are spending expensive CPU and sacrificing throughput to conserve DASD. As cheap as DASD is these days, perhaps the business case is to reduce/eliminate the need to do space management, reclaim that CPU, and generally speed up throughput.
As to Q2: Generally speaking, I trust the perception of an experienced operator. But only so far. Perhaps the mix of work is causing higher numbered drives to be allocated but never actually used. Whichever, I would want some numbers from a trusted measuring tool. But, why does anyone care? Just my $0.02 -----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of McKown, John Sent: Wednesday, June 01, 2005 9:20 AM To: IBM-MAIN@BAMA.UA.EDU Subject: Two questions: Q1 - DFHSM CPU usage; Q2 - Tape Allocation I know that asking two question is bad form. But I'm trying to "save a message slot". Both questions are about a z/OS 1.4 system. Q1: DFHSM CPU Utilization We are having a problem with DFHSM CPU utilization. It seems that no matter when we schedule PRIMARY SPACE MANAGEMENT, somebody complains. DFHSM runs as a high priority started task. This is so that recalls are handled quickly. I admit that I have not gone into the manuals yet. I'm am very pressed for time due to staff reductions <sorry>. So, is it possible to have two DFHSM started tasks? One would be high priority for recalls, the other a lower priority for PRIMARY SPACE MANAGEMENT. I know very little of DFHSM. If possible, is it "easy" or "a pain"? Thanks. Q2: Tape Allocation. We have four banks of 3490E tape drives. Each bank contains 8 drives. Each bank is attached to two CHPs which are dedicated to that bank of drives. I have been told that the "low address" tape drives appear to be allocated in preference to the "high address" tape drives. I cannot guarantee that the operators are not "messing around" using a VARY, but I have been told that they are not. Also I haven't seen any VARY command in the SYSLOG. So I assume that I am being told the truth. In the past, there was a SELTAPE parameter which disappeared long ago. Does this reuse of "low addressed" tape drives sound like what is supposed to be happening? If so, how to do tell z/OS to "spread the I/O" around? I used to have SELTAPE=NEXT. Again, due to other demands on my time, I have not had a chance to double check that I'm being told the truth. But the guy who is telling me this is a "reputable source" as the news-droids say. Thanks. Oh - will z/OS 1.6 make any difference? We are supposed to go to it something 3rd Q. -- John McKown Senior Systems Programmer UICI Insurance Center Information Technology This message (including any attachments) contains confidential information intended for a specific individual and purpose, and its' content is protected by law. If you are not the intended recipient, you should delete this message and are hereby notified that any disclosure, copying, or distribution of this transmission, or taking any action based on it, is strictly prohibited. ---------------------------------------------------------------------- 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
