Hi Team, Ive a question about mixing LTO drives and media in the same library LTOn and LTOn+2.
Windows TSM 5.4.3.2 (soon to be migrated to a 5.5.1.1 server running on AIX) IBM 3584 single frame library, presently with 4 x IBM LTO2 drives Currently no library clients or storage agents. My client is looking to migrate from 4 x LTO2 drives to 8 x LTO4 drives in their 3584 library (as well as performing some other TSM Server platform migration activities). The LTO drive generation-spanning capabilities are such that LTO4 drives can read from but not write to LTO2 media; that LTO2 drives can read/write to LTO2 media, but will have nothing to do with LTO4 media. Now, for an interim period, it has been suggested that the library be configured with 5 x LTO4 drives and 3 x LTO2 drives. TSM Server and the IBM 3584 Tape Library are both stated to support mixed media and tape drives between these LTO generations. However, the idea behind this is that during this interim period, new incoming backup data should be written to LTO4 media by the LTO4 drives (as well as some existing LTO2 data being moved/consolidated onto LTO4 media), and that offsite copies only continue to be generated to LTO2 media using the LTO2 drives (various reasons for this, including maintaining media compatibility for DR purposes). If possible, largely I think for flexibility, the preference is to achieve this within a single library partition. Its this last bit that Im having trouble getting my head around. Obviously, a new device class (FORMAT=ULTRIUM4C) will be added to the TSM Server to make use of the LTO4 drives (making sure that the current LTO2 device class is locked down to FORMAT=ULTRIUM2C), as will a new set of LTO4 storage pools pointing to this new device class. However, with both of these drive types being located in a single library partition I dont quite see how theyll be able to make sure that only LTO2 scratch tapes get mounted into LTO2 drives and that LTO4 drives dont go trying to write to LTO2 media. Is it simply a case of manually allocating the LTO2 scratch media to the LTO2 copy storagepool (and setting its MAXSCRATCH to 0), and ensuring that LTO4 is the only media in the general scratch pool? Will TSM ensure that, given were explicit in our device class definitions, when a backup stgpool operation requests a mount of an LTO2 scratch volume (or indeed an LTO2 filling volume) to perform a write itll only mount one into one of the LTO2 drives, and similar for LTO4 media and drives? I suspect not... Is anyone running with a similar configuration to this (if its possible)? Of course, the other blindingly obvious option is to partition the 3584, creating one library partition for the 3 x LTO2 drives and enough slots to manage the offsite requirement, and another for the 5 x LTO4 drives with the remainder of the carts. The client doesnt have ALMS for quick flexible library partitioning (I dont know about the cost of this feature, but I expect that theyd be unwilling to consider it for only an interim period) so wed have to use more rigid non-ALMS partitioning method. This option appeals to me in that its pretty simple to get my head around, but perhaps requires a little more work to perform the library repartitioning. Any thoughts gratefully received! Cheers, David Mc, London, UK No virus found in this outgoing message. Checked by AVG. Version: 7.5.524 / Virus Database: 270.11.18/2009 - Release Date: 18/03/2009 07:17
