We have been analyzing the possible uses of Virtual Tape, either the IBM VTS or the STK VSM. We are being very careful to select only data that is appropriate for virtual storage. "Appropriate," in this context, is defined as:
1. Data that is not required for disaster recovery. If you send your data to virtual storage, then you must have an identical virtual storage system available at your DR site. You would also need either the originals or duplicates of your virtual tape backups, plus tape backups of your virtual catalog. And even if you have the tapes and the virtual tape catalog, you will not have the data that existed only in the virtual system's buffer. 2. Data sets below a certain size, tentatively 1.6 gigabytes. The majority of data sets created are small, and the virtual system can help with this. If a data set is too large, it will go to the virtual system buffer, but then need to be written off to tape almost immediately. TSM gathers backups of many files, compresses them, and packages them as larger files. Thus you are using virtual, a good solution for many small data sets, for the wrong purpose. Virtual storage is a good tool when properly applied, but is not a cure-all. If it is not restricted to specific uses, it can cause many problems. -----Original Message----- From: MC Matt Cooper (2838) [mailto:[EMAIL PROTECTED]] Sent: Friday, November 30, 2001 7:59 AM To: [EMAIL PROTECTED] Subject: David, I remember reading in this list group that using a VTS with TSM is a very bad idea. I believe the issue was TSM data on disk being moved to the VSMs Disk (cache), overloading it. I would suggest looking through the list servers archives at http://search.adsm.org/ Matt -----Original Message----- From: David Browne. [mailto:[EMAIL PROTECTED]] Sent: Thursday, November 29, 2001 1:50 PM To: [EMAIL PROTECTED] Subject: I have three TSM servers running TSM 4.1.4 on OS390/MVS 2.10. Currently I write my onsite backups to dasd and then migrate the information to tape (3490E 36 track) for my onsite backups. My Storage Administer is wanting to move our onsite tape backups to a VSM. Our VSM is an STK Virtual Tape Manager and we are running HSC 4.1. We use SMS to control what datasets are selected to go to the VSM. Currently my TSM tapes are 3490E and the VSM is configured to look like a 3490 tape drive and 3490E tapes. Can I just let SMS send the mounts to the VSM? Has anyone done this? Blue Cross Blue Shield of Florida, Inc., and its subsidiary and affiliate companies are not responsible for errors or omissions in this e-mail message. Any personal comments made in this e-mail do not reflect the views of Blue Cross Blue Shield of Florida, Inc.
