rwo0@isg300.UUCP (Roger W. Otterson) (02/02/89)
I have recently been assigned the duty of backing up our system. We have a 3b2/522 w/ (6) 322mb SCSI drives. Needless to say it takes some time to do complete system backups. My backup device is a SCSI 9track tape drive. My questions are: How much can each tape hold (2400 or 3600 feet), and how do I guesstimate how much tape I will need to backup a file system. And what are the "magic" formulas to figure all of this out ?? Roger Otterson Information Systems Group
latzko@elbereth.rutgers.edu (Alex Latzko) (02/04/89)
In article <97@isg300.UUCP> rwo0@isg300.UUCP (Roger W. Otterson) writes: > I have recently been assigned the duty of backing up our system. > We have a 3b2/522 w/ (6) 322mb SCSI drives. Needless to say it > takes some time to do complete system backups. > > My backup device is a SCSI 9track tape drive. > > My questions are: > > How much can each tape hold (2400 or 3600 feet), and how do I The normal rule of thumb is a 2400' 1600bpi tape will hold 40Mbytes when blocked at 32Kbytes/block. 140Meg is the figure at 6250. You can figure it out if you know the lenght of a block in bytes and the number of blocks written in a group. The distance between blocks on the tape is called the inter record gap and if memory serves is 1/4 inches. > Roger Otterson > Information Systems Group cheers /S* latzko@rutgers.edu {backbone}!rutgers!latzko