On Tuesday 16 May 2006 15:43, Christoph Pilgram wrote: > Hi all, > > Because we have problems to hold our service level agreements with the > customers for restoring big file-servers (10 Mio files, 1TB disk-space > in one filesystem), we are thinking about storing the backups not > anymore on tape but on disk. Does anybody has experience with that kind > of storage-pool for about 40 TB of backup data ? Does anybody use for > example a "Data Domain DD460" or other systems using COS to reduce the > amount of data. We have lots of small customer with storage pools around 5TB. A LTO library with 2 tape drives can handle the backup, but the problem is restores. Restoring a file or a oracle db is ok. But for each restore, you have to check if a tape drive is free. And restoring multiple servers and/or file systems creates a mount point bottleneck.
The solution is to migrate existing customers to a SATA based SAN disk pool (DS4100, or similar) and doing disk-to-disk backup. The existing library can be used as electronic vaulting (if you can put the disk SATA pool and the library in a different building). For new customers, we are suggesting a SATA base disk pool and the smallest library (NOT tape loader) you can find with 1 tape drive for the offsite backups. (You only need 1 tape drive for the migration.) Right now I have a customer with a random storage pool on a DS4100 with SATA disks and it's running fine. I'm implementing an other one, also random storage pools on a DS4500 with also SATA disks. I'm not going for sequential disk pools because I don't want the overhead of reclamation. The SATA disk pools are on a remote SAN and if I have to do reclamation on a remote storage pool, I have to copy data 3 times over the SAN (1: backup, 2+3: relcamation). Stef
