Actually, it IS just a big chunk of SATA disk with sequential files, not a "formal" VTL. I should have explained, I was using "VTL" the concept, not "VTL" a product!
But I"ll give you my thinking, anyway: Advantages to using a VTL(the product): * The VTL software does compression for you. We have to set up our clients to do compression. If your client data isn't already compressed, and you are MOVING existing data from tape back to a pool of disk - it's gonna expand again. (We've been using client compression for the last year because I was planning for this.) * more of a "drop in" and forget it solution, less setup knowledge required (probably not an issue for very experienced TSM admins) Advantage of having "just a pool of disk" * probably more flexible in terms of being able to expand at will. We can add-replace drawers with bigger drives. We can add to our solution with disk from a different VENDOR if we want. My past experience is that the more generic and expandable your hardware solution, the longer you are able to get return on the investment. * I'm not jazzed that several of the VTL's on the market use software that comes from a from a 3rd party (shades of Emc buys Clarion buys Legato buys OTG etc. Just don't want to go there. Don't' want to have to think about what happens to my support 3 years from now.) BUT, our decision actually was determined by some VERY UNIQUE requirements we have for purging sensitive data if we need to. We create smaller LUNS than most people would so that we can segregate them and replace chunks of disk physically when we need to. (Don't ask.) In other words, we wanted more control over the internal placement of data. I think depending on your installation, either can be an excellent solution. If you need something relatively small, drop in, VTL is a better way to go (with a VENDOR YOU TRUST TO BE AROUND FOR A WHILE). If your shop doesn't have TSM skills, or time to think about it, a VTL is a better way to go If you are growing very fast, understand the technology, and need something with a lot of expandability, I would look more at building your own solution from building blocks you can be flexible with (and a VENDOR YOU TRUST TO BE AROUND FOR A WHILE). My opinions and nobody else's.. Wanda. -----Original Message----- From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED] On Behalf Of Leigh Reed Sent: Wednesday, February 15, 2006 5:32 AM To: ADSM-L@VM.MARIST.EDU Subject: Re: Offsite library via fiber (Specifically VTL) Wanda I would be intrigued to know your thoughts on why you went specifically with a VTL with TSM and not a more generic 'low cost' disk arrangement with sequential files. It is a decision that I am trying to come to terms with myself and have not yet settled in my mind which I prefer. Apart from price, if you take into consideration ease of management/configuration and performance, what decision making processes did those 2 variables lead you through. Did you go with IBM TS7510 or EMC CDL or a n other ? I guess the last $64M question is, are you happy with the decision you made ? Many thanks Leigh -----Original Message----- From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED] On Behalf Of Prather, Wanda Sent: 13 February 2006 19:31 To: ADSM-L@VM.MARIST.EDU Subject: Re: [ADSM-L] Offsite library via fiber We're doing just that. Easy to set up if your offsite location is within fibre distance. Only we are putting the VTL (primary pool) OFFSITE and the 3584 (copy pool) ONSITE. Why? 1) Tapes jam. Drives break. The 3584 is very reliable, but still mechanical. Easier to have it onsite, near us, to manage. The VTL is essentially lights out, so it will live offsite. 2) IF we have a disaster, having the VTL offsite means we can do DR restores without being limited by the number of tape drives we have. Cool idea, huh? Means we only need 2 drives in our 3584. Collocation & tape mounts are no longer an issue. And another cool thing: 3) We're even putting a spare Windows server offsite with the VTL, and making it a backup domain controller. TSM is already installed on it, but inactive. If we have a disaster, all we have to do is restore the TSM DB. We can start restoring files then to any machine we can get IP connectivity to. Our domain is still up, we don't have to recover AD. I can hardly wait for the tornado! Wanda Prather "I/O, I/O, It's all about I/O" -(me) -----Original Message----- From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED] On Behalf Of David E Ehresman Sent: Friday, February 10, 2006 3:54 PM To: ADSM-L@VM.MARIST.EDU Subject: Offsite library via fiber We're thinking of a TSM upgrade that would include a VTL onsite library and an IBM 3584 library for copy pool tape. We would locate the 3584 in our offsite storage location and access it via fiber. The tapes would remain in the 3584 since they would already be offsite. Anyone have any experience with a setup like this? Daivd Ehresman University of Louisville