We have been using a VTL for 3-4 months and we consider it a success. Environment: ------------------------------------------------------------------------ -------- * OS: AIX 4330-11 * TSM: Version 4, Release 2, Level 1.7 * Physical Library: Single frame 3494 w/2 3590E1A Drives * VTL: Sepaton ES2100 10.5TB (Raw) * VTL Drive Config: 50 Drives * VTL Tape Vol Size: 10 GB (picking a size is a religious belief) * VTL Tape Volume Quantity: 839 * Avg Nightly Backup Amt: ~750 GB * Client Types: AIX, Windoze(NT, 2000, 2003), Oracle (TDP), . Microsoft SQL (TDP), Novell * Collocation: None * Total Primary Stg Amt: ~10.3 TB
Problems Leading Requiring Upgrade/VTL Purchase: ------------------------------------------------------------------------ -------- * Poor restoration speed for file servers due to: - No use of collocation because of single frame 3494, amt of primary stg, desire . to make tape management simple (read desire tape library to house all primary . tape volumes, no overflow to a cabinet/vault) - Only 2 drives - Both drives spinning tapes 95%-99% of day doing migrations, backups and . reclamations, leaving little time for restorations. * Poor offsite reclamation performance: Offsite tape count growing to ~500 with . >400 being >50% reclaimable * Onsite tape count growth forcing expansion of existing library/purchase of new . library and associated disk stgpool Reasons Pushing to VTL over DASD and Physical Library: ------------------------------------------------------------------------ -------- * Ability to do LAN Free back-ups w/o Sanergy * Storage compression w/o load on TSM server or client * Performance: Mounts/Unmounts, Reads, Writes (Comparison with physical tapes . need to keep in mind your clients/server may not be able to continuously . stream data to tape. * Desire to break out of the structure where growth requires growth of library . system AND disk stgpool * Ease of implementation Benefits Realized: ------------------------------------------------------------------------ -------- * All of the problems requiring the upgrade have been eliminated * All primary stg pool data has been moved to the VTL * 3494 is only used for the offsite COPYPOOL stgpools and offsite DB back-ups * offsite COPYPOOL reduced to ~195 tapes with ~5 being >50% reclaimable * 3494 drives no longer have to spin 95% of the day * Back-up and restorations greatly improved w/o use of collocation * Implementation was easy: - VTL was TSM certified just like a physical library - VTL install and config: ~1 hours - TSM Config (Library, Drives, stgpool): ~20 minutes - TSM labeling of 839 volumes: ~2 hours - ~2 minutes to update the NEXT STGPOOL on the primary disk stgpools to point to . VTL stgpool We viewed the costs of the VTL vs. a physical library with drives (that performs like the VTL) and associated disk stgpool to be comparable. Needless to say, I disagree with the statement that TSM doesn't appear to be a good fit for a VTL. Remember a VTL is just a library that can mount/unmount a tape in less than one second and read/write to the tape at disk speeds. Why wouldn't TSM work well with a library on steroids? Thanks, H. Milton Johnson -----Original Message----- From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED] On Behalf Of David E Ehresman Sent: Monday, November 29, 2004 2:42 PM To: [EMAIL PROTECTED] Subject: Re: size of active vs. inactive? >>It has also been discussed several times that TSM doesn't appear to be a good fit for a VTL. May want to search the archives to find out more on the subject.<< Has anyone heard of good experiences with TSM on a virtual tape library? Can this ever be a good thing?
