When step initiation occurs it builds the TIOT for all the data sets. Each TIOT entry for a DDNAME has the UCBs for all the volumes associated with that DDNAME. In the case of a NEW dataset, it has to build a candidate list for all the volumes to be assigned to that DDNAME. Thus it is hard for the system to assign 5 volumes to a data set when there are only 2 volumes to choose from.
Other considerations that go on are it validates that the volumes it assigns have the primary allocation space available at the time it makes the assignment. If you have a primary amount of 500 cylinders and specify UNIT=(GROUP1,5) and GROUP1 has 25 volumes in it, but only 3 have 500 cylinders available in 5 extents or less, then the allocation will fail. Personal opinion and experience only. ________________________________ Christopher Y. Blaicher Senior Software Developer Austin Development Lab phone: 512.340.6154 moble: 512.627.3803 fax: 512.340.6647 10431 Morado Circle Austin, TX 78759 BMC Software -----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Gilbert Cardenas Sent: Tuesday, September 02, 2008 9:41 AM To: [email protected] Subject: Discussion on Mod 27 usage I know there has been some recent discussions on the usage of Mod 27s and my question is somewhat related so I'm looking for some insight. Background: We recently added more storage to our Shark and we initialized all of the new volumes as Mod 27s. I migrated several storage pool volumes to the new mod 27s so some of the storage pools went from 10 volumes per say to 2 volumes. Observations: We ran into an issue this weekend where one of our DB2 jobs abended with a IEC028I 837-08 error code. From all indications there was plenty of space available but after looking at the control cards, the jcl was specifying a volume count of 5 but there were only 2 volumes in the pool available. It was my understanding that specifying a volume count would only allow the job to utilize that many volumes if they were available. Not that that many volumes would be a requirement. Questions: Would jcl that is specifying a volume count more than what is available cause this type of abend? Are there other gotchas I need to look out for? Can anyone shed some light on this? Thanks, Gil. ---------------------------------------------------------------------- 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
