Ted, I understood the problem. The unit count as specified in the dataclas or JCL, or calculated from used and candidate volumes in the catalog, uses space in the TIOT. If your job has 50 datasets with a unit count of 40, then the space used in the TIOT will be equivalent to 2000 volumes.
The issue is provisioning for every dataset to be multi-volume across 20 units, or in your case 40. If a dataset is cataloged with one used volume and 19 candidates, then it is the same as having a 20 volume dataset. Ron > -----Original Message----- > From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of > Ted MacNEIL > Sent: Tuesday, June 23, 2009 1:00 PM > To: [email protected] > Subject: Re: [IBM-MAIN] SMS Dataset Allocation Problem > > >It was not DB2 that had a problem. It was CICS and a few batch jobs. > > Okay. I stand/sit corrected. > > >I don't have a problem with multi-volume datasets at all, and in fact I > design SMS > to allocate large datasets on as many volumes as possible. > > I didn't think you did have a problem. > The issue is not multi-volume; it's number of volumes. > > > >It was simply having so many candidate volumes for every dataset, 1 track or > 1 pack, was excessive and we started having TIOT blow outs. > > Were you using the max TIOT size? > I believe it's 64K. > > >I think we were using 20 for the unit count when the problem happened. > > While I've said we've used 59, usually I've used 20, but that's for Batch. > For online, we left it up to apps/DBA, except for DB2, since it uses a > different method. > - ---------------------------------------------------------------------- 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
