Determining the number of tapes for the backup

You must determine the number of tapes required for the backup before entering the dump command for these reasons:

You can ensure that the dump command will not run out of tapes and be incomplete.
You can load all tapes required in the tape drives or stackers in advance for an unattended backup. If you do not load enough tapes before entering the dump command and you start the dump command from the console, the filer prompts you to load additional tapes. If you start the dump command through rsh, you do not see the prompts from the filer and the dump command cannot be completed because of the lack of tapes.

You must meet these prerequisites before you can determine the number of tape files required:

The filer must be able to display tape drive information. To learn how to display tape drive information, refer to "Displaying tape device information."
You must know the amount of data to be backed up. For information about determining the amount of backup data, refer to "Determining the amount of backup data."

Follow these steps to determine the number of tapes required for the backup.


Step	Action
1	Determine the capacity of the tape drives you are using for the backup.
2	Determine the amount of data that needs to be backed up.
3	Determine the amount of space that will be left unused on a tape. For example, if the `dump` command specifies several tape files, the command automatically writes to the next tape file even though there is space left in the current tape. Example The following `dump` command starts the second tape file on `rst1a` after writing 2,000,000 tape blocks to the first tape file, even though the tape in `rst0a` contains unused space: dump 0ufB rst0a,rst1a 2000000 /vol/vol0

Part No. 210-02334
File: dump5.htm
Last updated: 02/24/99 12:17:01