Subject: VSAM limits
From: Edward M Martin (EMartin@aultman.com)
Date: Thu Nov 05 2009 - 16:27:12 EST
Hello Everyone, Seems we were discussing some VSAM limits on files that had not reached the 4 gig limit. Here are some more. The lock used by Shareoption(4) processing has a two byte field for the control area id (or index control interval id for KSDS files). Thus, a Shareoption(4) file may not have more than 64511 (64K-1024) control areas, and the maximum file size would be 64511 times your control area size. If you use the maximum control area size for your file of one cylinder, define the file as XXL, and reside on 3380, with a CISIZE of 4K, this would set a maximum file size of 36.9GB. In addition, any single allocation (primary or secondary) cannot contain more than 16Meg records, if the user intends on using Backup/Restore. See APARs DY36234 and DY40943. When defining files using RECORDS(..), you can only specify up to 16 million records per extent. You can request more data by specifying a larger maximum recordsize for the file. Ed Martin Aultman Health Foundation 330-363-5050 ext 35050
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