Hi, We originally allowed MIDAW support to default on for z/OS R6 but disabled it when we ran into a possibly related problem with DB2 V8 from APAR OA15034. IMHO the default should have been disabled in R6 & R7 and changed to enabled in R8. The problem with DB2 V8 here turned out to produce similar symptoms but was unrelated to MIDAW. In researching the problem we became aware of a couple APAR's we felt warranted keeping MIDAW off in our environment. It is a cool feature if you have the hardware (z9) & software (R6+),it should produce measurable improvements, it should be perfectly safe for most everyone to use. We just decided to be extra cautious and keep it disabled till we could get fixes for some recent APARs and get those fixes rolled across the sysplex. We have a mixed environment with both MIDAW capable (IBM) and non MIDAW capable (HDS) DASD.
This was the one that got us concerned and caused us to disable MIDAW initially. The PTFS became available recently and we don't have them rolled out into the production Sysplex yet so it is still disabled in parmlib. APAR Identifier ...... OA15034 Last Changed ........ 06/04/03 IO ERRORS ON MULTIVOLUME LINEAR DATA SETS WITH MIDAW SUPPORT ENABLED. D/T2094 Symptom ...... LP LOOP Status ........... CLOSED PER Severity ................... 1 Date Closed ......... 06/02/08 Component .......... 5695DF106 Duplicate of ........ Reported Release ......... 1J0 Fixed Release ............ 999 Component Name DFSMS VSAM MEDA Special Notice HIPER Current Target Date ..06/02/17 Flags SCP ................... FUNCTIONLOSS Platform ............ Status Detail: SHIPMENT - Packaged solution is available for shipment. PE PTF List: PTF List: Release 1J0 : UA24319 available 06/03/07 (F603 ) Release 1K0 : UA24320 available 06/03/07 (F603 ) Other APARs of "interest" for MIDAW. APAR Identifier ...... OA15447 Last Changed ........ 06/03/22 COMMAND REJECT, INVALID PARM FOR A LOCATE RECORD EXTENDED CHANNEL PROGRAM. MULTIPLE IOS000I MESSAGES RECEIVED. D/T2094 Symptom ...... MS MSGIOS000I Status ........... CLOSED PER Severity ................... 3 Date Closed ......... 06/03/22 Component .......... 5695DF106 Duplicate of ........ Reported Release ......... 1K0 Fixed Release ............ 999 Component Name DFSMS VSAM MEDA Special Notice HIPER Current Target Date ..06/04/30 Flags SCP ................... FUNCTIONLOSS Platform ............ Status Detail: TESTPACKAGING - Packaged solution is being tested. PE PTF List: PTF List: Release 1J0 : PTF not available yet Release 1J0 : Relief is available in the form of: AA15447 Release 1K0 : PTF not available yet Release 1K0 : Relief is available in the form of: AA15447 APAR Identifier ...... OA15505 Last Changed ........ 06/04/03 2084 DISPLAYS MIDAW CHAINS IN GTF OUTPUT D/T2094 Symptom ...... IN INCORROUT Status ........... CLOSED PER Severity ................... 2 Date Closed ......... 06/03/03 Component .......... 5752SC111 Duplicate of ........ Reported Release ......... 720 Fixed Release ............ 999 Component Name 5752 GTF Special Notice Current Target Date .. Flags SCP ................... Platform ............ Status Detail: SHIPMENT - Packaged solution is available for shipment. PE PTF List: PTF List: Release 709 : UA24825 available 06/03/14 (F603 ) Release 720 : UA24826 available 06/03/14 (F603 ) APAR Identifier ...... OA15556 Last Changed ........ 06/03/31 BUILD MIDAWS IN SEPERATE PAGE FROM CHANNEL PROGRAM TO IMPROVE PERFORMANCE IN DB2 ENVIRONMENT D/T2094 Symptom ...... NF NEWFUNCTION Status ........... CLOSED UR1 Severity ................... 2 Date Closed ......... 06/03/31 Component .......... 5695DF106 Duplicate of ........ Reported Release ......... 1J0 Fixed Release ............ 999 Component Name DFSMS VSAM MEDA Special Notice Current Target Date ..06/05/06 Flags SCP ................... Platform ............ Status Detail: TESTPACKAGING - Packaged solution is being tested. PE PTF List: PTF List: Release 1J0 : PTF not available yet Release 1K0 : PTF not available yet ======================================================================== ===== Best Regards, Sam Knutson, GEICO Performance and Availability Management mailto:[EMAIL PROTECTED] (office) 301.986.3574 "Think big, act bold, start simple, grow fast..." -----Original Message----- Re: batch performance, another new item in the bag of tricks is MIDAW. ==================== This email/fax message is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution of this email/fax is prohibited. If you are not the intended recipient, please destroy all paper and electronic copies of the original message. ---------------------------------------------------------------------- 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