<[EMAIL PROTECTED]> wrote in message news:<[EMAIL PROTECTED] e.fl.us>... > The virtual tape mount question in the SMF JWT thread prompted me to post > this: > > We're thinking about moving off virtual tape, to Tape Mount Management. > We've been kicking the idea around because: > > 1. We think we have the DASD to accomodate an x-day buffer of user tape > 2. All of our important backups and migrations (we are FDR/ABR) go > directly to 9840 > 3. DR of virtual tapes is kind of a pain > 4. Since the advent of PC workstations and servers, users "grasp" the idea > of online disk datasets, but don't quite grasp files on tape. Plus their > DASD datasets would be available faster (no tape mounts), > > TMM and virtual tape are conceptually identical (to us anyway) - both use > a DASD buffer to eliminate tape mounts and both use system-managed storage > techniques to manage that DASD buffer. The main difference is that a VTS / > VSM system uses SMS logic defined by the vendor rather than by us. > > We think we would use the savings from dropping the virtual tape hardware > to purchase more drives and/or another STK LSM if we needed it to > accomodate increased backup activity (although in our case we might not > need it). Additional drives would shorten our backup and migration times, > which is a plus for this scenario. > > So - that's _our_ thinking on the topic, but I'd be interested to hear the > opinions - and we _know_ this list has them - on the topic of migrating > away from virtual tape... > >
A couple of thoughts: - Why do you send your migrations to 9804? We run CA-DISK and I don't know ABR, but you can: 1. Migrate to disk. This will roughly decrease the space, since idle space is dropped and you can also compress the data if you can spend the CPU costs. This delivers fast recall times, so you can possibly migrate more aggressively. 2. Migrate to VTS and set up rules to keep the data in the cache. This will also deliver fast recall times and at the same time, much faster than from 9840 and you can possibly migrate more aggressively. - VTS storage is cheaper than online Dasd, so from the cost point, VTS is preferred about TMM. - If your recalltimes from VTS, are a problem because they cannot be done from the cache, you might spend your money on enlarging the cache in stead of the TMM buffer. - DR is possible with a peer-to-peer VTS (VSM) configuration if you can put them far enough apart from each other and can be handled by the VTS. What is your DR procedure now, with the backups and migrations directly to 9840? - Have a look at the new TS7700 from IBM. This has enhanced the Virtual Tape concept considerably, both for normal operation and for DR. Kees. ********************************************************************** For information, services and offers, please visit our web site: http://www.klm.com. This e-mail and any attachment may contain confidential and privileged material intended for the addressee only. If you are not the addressee, you are notified that no part of the e-mail or any attachment may be disclosed, copied or distributed, and that any other action related to this e-mail or attachment is strictly prohibited, and may be unlawful. If you have received this e-mail by error, please notify the sender immediately by return e-mail, and delete this message. Koninklijke Luchtvaart Maatschappij NV (KLM), its subsidiaries and/or its employees shall not be liable for the incorrect or incomplete transmission of this e-mail or any attachments, nor responsible for any delay in receipt. Koninklijke Luchtvaart Maatschappij N.V. (also known as KLM Royal Dutch Airlines) is registered in Amstelveen, The Netherlands, with registered number 33014286 ********************************************************************** ---------------------------------------------------------------------- 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
