Data Backup12-11
5HFRPPHQGDWLRQVIRU3HUIRUPLQJD%DFNXS
$ERXW7KLV6HFWLRQ
Some recommendations in this section are applicable to all kinds of backups; some
recommendations depend on your priorities, such as your need to minimize backup
time or to minimize tape handling.

*HQHUDO5HFRPPHQGDWLRQV

Follow the recommendations in this section when you back up data from the filer.

$YRLG%DFNLQJ8S7RR0XFK'DWDLQD6LQJOH'XPS&RPPDQG

The reasons are listed below:
The dump command cannot be restarted. That is, if the dump command encoun-
ters an error, you cannot correct the error and proceed from the point where the
command fails. You must start the command from the beginning.
The backup takes a long time to finish. This leaves you with a long time period
during which changed data cannot be written to tape by an incremental backup.

6WRUH,QFUHPHQWDO%DFNXSVIRUWKH6DPH'XPS3DWKRQWKH6DPH7DSH

If you want to do a subtree restore, you must restore from all incremental backups to
restore the most recent data. Having all the incremental backups in the same tape
minimizes tape management during the restore process.

:ULWH'RZQ4WUHH,QIRUPDWLRQ%HIRUH%DFNLQJ8STWUHHV

Record the information about qtrees if your backup contains qtrees. This is because
when you restore data from tape, the filer does not automatically re-create the qtrees.
You must re-create the qtrees into which data is to be restored. Having a record of all
qtrees enables you to re-create the qtrees quickly.

5HFRPPHQGDWLRQVIRU0LQLPL]LQJ%DFNXS7LPHDQG'DWD

/RVV

The recommendations in this section enable you to minimize both the time required
to perform a backup and the possibility of data loss. This is because the shorter the
time for the dump command to finish, the more incremental backups you can
perform. A large number of incremental backups minimize the amount of unrecover-
able data.
NOTE: There is a disadvantage to having a large number of incremental backups:
When you restore data, you must restore from all the incremental backup tapes,
which might take a long time.