Subject: RE: VSAM - IDCAMS Backup Puzzle
From: David Stuart (David.Stuart@ventura.org)
Date: Wed Sep 02 2009 - 12:44:42 EDT
Hi Kevin, Density is a good point. Hadn't thought about that. Cat2 is full of Virtual Tape files, written/managed by Jeff Barnard's OptiTape product. Cat1 is regular COBOL VSAM files. Dave Dave Stuart Prin. Info. Systems Support Analyst County of Ventura, CA 805-662-6731 David.Stuart@ventura.org>>> "Kevin Corkery" <kcorkery@live.com> 9/2/2009 9:18 AM >>> Hey Dave ... Looks like a good argument for new tape drives. Anyway, the density of the data in the files in catalog 2 may be higher than those in catalog 1. I know that IDCAMS processes at the CI-level but it likely only writes a variable length record that contains the data. The denser the data in packed into the control intervals the more data needs to be written to the backup. The less dense catalog could show more space allocated and occupied but there could be less data in each CI. This is a possible explaination but given the ratio you're seeing I don't think it's necessarily the correct explanation. Do you have enough virtual tape space available? It would help remove the physical tape technology out of the picture. Kevin P. Corkery Independent Consultant Voorhees, NJ 08043 -----Original Message----- From: owner-vse-l@Lehigh.EDU [mailto:owner-vse-l@Lehigh.EDU] On Behalf Of David Stuart Sent: Wednesday, September 02, 2009 11:37 AM To: VSE Discussion List Subject: RE: VSAM - IDCAMS Backup Puzzle Hi Ed, If you're referring to VSAM Compression, we do not have any compressed VSAM files. Good idea, though. Dave Dave Stuart Prin. Info. Systems Support Analyst County of Ventura, CA 805-662-6731 David.Stuart@ventura.org>>> "Edward M Martin" <EMartin@aultman.com> 9/2/2009 6:31 AM >>> Hello Dave and the list, Please correct me if this is wrong, but I believe that if you have compressed files on the VSAM catalog, that they are uncompressed going to the BACKUP tape. Then the 3480 will us hardware compression to place them on the tape. Could it be that you have lots of files compressed on CAT2 and none that are compressed on CAT1? Ed Martin Aultman Health Foundation 330-363-5050 ext 35050 -----Original Message----- From: owner-vse-l@Lehigh.EDU [mailto:owner-vse-l@Lehigh.EDU] On Behalf Of David Stuart Sent: Tuesday, September 01, 2009 5:30 PM To: VSE Discussion List Subject: VSAM - IDCAMS Backup Puzzle Afternoon, We have something going on with IDCAMS Backup that has us puzzled. We have two VSAM Catalogs involved: Cat1 - 5 volumes, @350 files, 44% free space, files are pretty evenly spread across all 5 volumes (thank you, VSE Navigator!). Cat2 - 5 volumes, @135 files, 54% free space, files are on volumes 1 - 3. Volumes 4 and 5 are empty. Cat1 - The IDCAMS Backup takes 7 - 9 cartridges. Cat2 - The backup averages 24 cartridges. All Disk volumes reside on a DS6800, and are defined as 3390-3. Tape drives are IBM 3480-B22 with IDRC active. Ditto shows that the cartridges are 'compacted' with IDRC. The IDCAMS Backup JCL is defined the same for both catalogs: Backup (*) Blksz(65535) Buffers(8) Nocompact The Tape Datasets are defined the same way to Dynam/T with Density 08, IDRC/compacted. We've tried changing various JCL settings for Cat2, but the backups still come out the same: Cat1 - 7 - 9 cartridges, Cat2 - @24 cartridges. Ideas? TIA, Dave Dave Stuart Prin. Info. Systems Support Analyst County of Ventura, CA 805-662-6731 David.Stuart@ventura.org
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