Just to put an end to this discussion, we're kinda running out of limits here: a) No VTL solution, neither DD, neither Sepaton, neither anyone, is a replacement for random diskpools. Doesnt matter if you can configure 50 drives, 500 drives or 5000 drives, the way TSM works, you're gonna make the system go bad since the system is made from having random pools infront, sequential pools in the back. A sequential device is not gonna replace that, independent being a sequential file pool or a VTL (or, for that question, a tape library). b) VTL's where invented because most backup software (I've only worked with TSM, Legato & Veritas aka Symantec) is used to working with sequential devices. That havent changed, and wont change in the near future. VTL's (and the file device option) is just a replacement. Performance wise, VTL's are gonna win all the time compared to a file device, question you need to ask yourself is, do I need the VTL, or can I go along with using file devices. According to the TSM manual (dont have the link , but if you want i'll find it) the maximum supported file device pool for deduplication is 6TB... so if you're thinking of replacing a VTL with a seq. file pool, keep that in mind. The limit is because the amount of resources needed by TSM to do the file deduplication is limited, or as the manual says, "until new technologies are available". The discussion here where people are actually planning on just having a sequential pool (since noone is actually discussing that there's a random pool infront) is plain scary. No sequential device is gonna have their time of the life having a fileserver serving 50K blocks at a time. So my last 50 cents worth is: a) Have a random pool infront b) Depending on the size of your environment, you're either gonna go with a filepool and use de-dup (limit is 6TB for each pool, you might not want to de-dup everything), or you're gonna go with a fullscale VTL. Choice here is size vs costs. I've seen alot of posts here lately about the disadvantages with VTL's .. well, I havent seen one this far with mine. I have a colleague who bought a XXXX VTL and found out he needed another VTL just todo the de-dup, since one VTL wasnt a supported configuration to do de-dup. I have another colleague who bought a very cheap VTL solution (from a very mentioned name around here) and ended up with having same hashes, but different data, leaving him with unrestorable data. Comparing eggs to apples just isnt fair. Different manufactures of VTL's do different things, meaning both performance and availability is completely different. Just to sum up, we've had both 3584's and (back in the days) 3575, and I've never been happier with our VTL (and yes, we do restore tests). Best Regards Daniel
Daniel Sparrman Exist i Stockholm AB Växel: 08-754 98 00 Fax: 08-754 97 30 daniel.sparr...@exist.se http://www.existgruppen.se Posthusgatan 1 761 30 NORRTÄLJE -----"ADSM: Dist Stor Manager" <ADSM-L@VM.MARIST.EDU> skrev: ----- Till: ADSM-L@VM.MARIST.EDU Från: Rick Adamson <rickadam...@winn-dixie.com> Sänt av: "ADSM: Dist Stor Manager" <ADSM-L@VM.MARIST.EDU> Datum: 09/27/2011 18:02 Ärende: Re: [ADSM-L] Ang: Re: [ADSM-L] vtl versus file systems for pirmary pool Interesting. Every VTL based solution, including data domain, that I looked at had limits on the amount of drives that could be emulated which were nowhere near a hundred let alone a thousand. Perhaps it's time to revisit this. The license is a data domain fee, and a hefty one at that. The bigger question I have is since the file based storage is native to TSM why exactly is using a file based storage not supported? ~Rick -----Original Message----- From: ADSM: Dist Stor Manager [mailto:ADSM-L@VM.MARIST.EDU] On Behalf Of Daniel Sparrman Sent: Tuesday, September 27, 2011 10:30 AM To: ADSM-L@VM.MARIST.EDU Subject: [ADSM-L] Ang: Re: [ADSM-L] vtl versus file systems for pirmary pool Not really sure where the general idea that a VTL will limit the number of available mount points. I'm not familiar with Data Domain, but generally speaking, the number of virtual tape drives configured within a VTL is usually thousands. Not sure why you'd want that many though, I always prefer having a small diskpool infront of whatever sequential pool I have, and let the bigger files pass the diskpoool and go straightly to the seq. pool. As far as for LAN-free, the only available option I know of is SANergy. And going down that road (concerning both price & complexity) will probably make the VTL look cheap. Not sure what kind of licensing you're talking about concerning VTL, but I assume it's a Data Domain license and not a TSM license? Best Regards Daniel Sparrman Daniel Sparrman Exist i Stockholm AB Växel: 08-754 98 00 Fax: 08-754 97 30 daniel.sparr...@exist.se http://www.existgruppen.se Posthusgatan 1 761 30 NORRTÄLJE -----"ADSM: Dist Stor Manager" <ADSM-L@VM.MARIST.EDU> skrev: ----- Till: ADSM-L@VM.MARIST.EDU Från: Rick Adamson <rickadam...@winn-dixie.com> Sänt av: "ADSM: Dist Stor Manager" <ADSM-L@VM.MARIST.EDU> Datum: 09/27/2011 16:52 Ärende: Re: [ADSM-L] vtl versus file systems for pirmary pool A couple of things that I did not see mentioned here which I experienced was.... for Data Domain the VTL is an additional license and it does limit the available mount points (or emulated drives), where a TSM file based pool does not. Like Wanda stated earlier depends what you can afford ! I myself have grown fond of using the file based approach, easy to manage, easy to configure, and never worry about an available tape drive (virtual or otherwise). The lan-free issue is something to consider but from what I have heard lately is that it can still be accomplished using the file based storage. If anyone has any info on it I would appreciate it. ~Rick Jax, Fl. -----Original Message----- From: ADSM: Dist Stor Manager [mailto:ADSM-L@VM.MARIST.EDU] On Behalf Of Tim Brown Sent: Monday, September 26, 2011 4:05 PM To: ADSM-L@VM.MARIST.EDU Subject: [ADSM-L] vtl versus file systems for pirmary pool What advantage does VTL emulation on a disk primary storage pool have as compared to disk storage pool that is non vtl ? It appears to me that a non vtl system would not require the daily reclamation process and also allow for more client backups to occur simultaneously. Thanks, Tim Brown Systems Specialist - Project Leader Central Hudson Gas & Electric 284 South Ave Poughkeepsie, NY 12601 Email: tbr...@cenhud.com <<mailto:tbr...@cenhud.com>> Phone: 845-486-5643 Fax: 845-486-5921 Cell: 845-235-4255 This message contains confidential information and is only for the intended recipient. If the reader of this message is not the intended recipient, or an employee or agent responsible for delivering this message to the intended recipient, please notify the sender immediately by replying to this note and deleting all copies and attachments.
