Acronis Backup & Recovery

Tape planning

Once you have specified the backup scheme and tape options, you should determine the minimal number of tapes necessary to achieve full automation of tape rotation.

To simplify the tape planning lets discard the possibility that the calculated tapes might contain backups of other data. It is implied that the Use a separate tape set option is enabled.

To calculate the number of tapes you should take into account the following considerations:

• full backup size
• average size of incremental backups
• average size of differential backups
• compression level specified for backing up the data
• tape rotation scheme ( frequency of backups, retention rules)
• tape-append options
• requirements to support off-site tape cartridge archives.

There is no common formula to calculate a number of tapes required in all possible combinations of above listed considerations. But the general way to get a number of tapes for a case includes the following steps:

1. Draw (or write) a chain of backups until the first backup can be deleted
2. Take into account the tape-append options, the chain might be sectioned onto tape sets
3. Calculate the number of tapes in each tape set
4. The sum of the calculated values gives the total number of tapes required for the case.