The logical volumes in a VTS and backend physical tape still work like a real tape in that even if the tape is scratch the data remains accessible until the volume is rewritten. I believe there is an option in the VTS to retain only volume header after a tape is scratch but I could be wrong. If you are not rewriting or deleting tapes then you usage will not change and reclaim will do nothing other than shuffle the same data around,
CIT | Ken Porowski | VP Mainframe Engineering | Information Technology | +1 973 740 5459 (tel) | [email protected] This email message and any accompanying materials may contain proprietary, privileged and confidential information of CIT Group Inc. or its subsidiaries or affiliates (collectively, "CIT"), and are intended solely for the recipient(s) named above. If you are not the intended recipient of this communication, any use, disclosure, printing, copying or distribution, or reliance on the contents, of this communication is strictly prohibited. CIT disclaims any liability for the review, retransmission, dissemination or other use of, or the taking of any action in reliance upon, this communication by persons other than the intended recipient(s). If you have received this communication in error, please reply to the sender advising of the error in transmission, and immediately delete and destroy the communication and any accompanying materials. To the extent permitted by applicable law, CIT and others may inspect, review, monitor, analyze, copy, record and retain any communications sent from or received at this email address. -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Robert A. Rosenberg Sent: Wednesday, January 28, 2015 12:29 AM To: [email protected] Subject: Re: [IBM-MAIN] 3494 tape library with B20 VTS At 19:54 +0000 on 01/27/2015, Pommier, Rex wrote about 3494 tape library with B20 VTS: >Hi all, > >I have a couple questions about tape reclamation and statistics. We >have a 3494 tape library that is currently exclusively being used as >physical (stacked) tapes for a 3494-B20 VTS. We're in the process of >migrating off this hardware so we have no new allocations going to the >B20 and subsequently to the 3590 tapes behind it in the 3494. >So as to minimize the churn in the physical tape library, we >essentially have tape reclamation shut off. In looking at the graphs >generated on the 3494 console, I'm not seeing either the "active data >distribution (count of tapes and the percentage of active data on >them)" or the "active data (Gigabytes of active data in the library)" >going down. I know we have taken a significant amount of data out of >the library over the past 30 days, either by migrating it to our >replacement library or by deleting/scratching logical tapes that we >deemed unnecessary. > >So my question is this: Should I be seeing these numbers dropping or >will they not drop because I'm not reclaiming tapes? > >TIA, > >Rex Since you have multiple logical tapes stacked on each physical tape volume, what you are seeing is what you should expect so long as you do not allow the logical tape volumes to be migrated to new physical volumes. So long as each physical volume has at least one logical tape on it, it can not be reclaimed. As suggested temporarily turn on tape reclaim and let the logical tapes migrate by moving them to other physical tapes. This will allow the volumes with few logical tapes on them to be completely emptied and thus reclaimed. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
