HP B6960-96035, Руководство по концепциям

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Figure 100 Backup generations
You configure Data Protector to automatically maintain the desired number of backup
generations by selecting the appropriate data and catalog protection durations, and
scheduling for unattended backups, both full and incremental.
For example, to keep three backup generations while you have weekly full backups
and daily leveled incremental backups, specify data protection to 7*3+6=27 days.
A backup generation represents a full backup and all incremental backups until the
next full backup: therefore, the six in the formula represents incremental backups
before the next, fourth, backup generation belonging to the third backup generation.
You can set automatic media rotation (for the media with expired protection time)
through an appropriate pool usage concept. For more information, see “
Implementing
a media rotation policy ” on page 143.
Examples of automated media copying
After a backup finishes, you can use the automated media copy functionality to copy
the media, and then move either the originals or the copies to an off-site vault. You
can use either post-backup or scheduled media copying, depending on the availability
of devices.
The considerations that must be taken into account are the following:
• It is recommended to perform all backups first and then copy the media.
• During media copying, the media that are being copied are unavailable for
restore.
• You can only copy the entire medium, and not specific objects.
• After the copying, the source media that are copied and the copies are marked
as non-appendable, which means that you cannot append new backups to these
media.
• With scheduled media copying, the necessary devices and media must be
available at the scheduled time, otherwise the copy operation will be aborted.
Further information 332