HP StorageWorks NAS 1000s, Руководство администратора, Страница: 156 / 172

Backup Management
156 NAS 1000s Administration Guide
Backup Schedules
An automatic, periodic backup is much more reliable than occasional backups that occur only
when someone remembers to execute them. The specific needs of the organization will
determine what type of schedule to implement.
A weekly or biweekly full backup is the basis of any good backup schedule. Add to that
baseline daily incremental or differential backups to capture any daily changes that occur
between full backups. Depending on the rate of data change, and the capacity and performance
of the backup devices, adjust the backup schedule to fit the environment of the organization.
Incremental backups capture changes to the data that have occurred since the last backup.
Differential backups capture all the changes that have occurred since the last full backup.
If the backup devices do not have sufficient capacity for a complete, full backup, distribute the
backups so they occur throughout the backup cycle. This strategy can meet the backup needs
of the organization until a larger tape backup device or library can be installed. For example,
instead of doing a full backup of disks C:, X:, Y:, and Z: on Friday, back up C: on Monday, X:
on Tuesday, Y: on Wednesday, and Z: on Thursday. Schedule incremental or differential
backups on the same distributed schedule.
Note: The suggested scenarios for backup times are based on a hypothetical company situation.
Media Rotation
Most backup software solutions are equipped to label and track media usage accurately. Take
advantage of these capabilities to maintain different media pools for full backups and
incremental/differential backups, as well as archive media. The retention time on each of these
types of backup is different. For example, using differential backups on the same tape as for
full backups causes the tape space to be wasted after the retention time for the differential data
has passed. Keep separate pools to avoid this problem.
Offsite Storage
Set up a regular process for moving important long term media, such as backups and archives,
offsite for safekeeping. This ensures that the administrator can recover the data in the event of
a complete facility destruction where the NAS device resides. As an alternative to a
commercial offsite storage facility, if the company has multiple buildings, the offsite media
can be stored in another building. This alternative provides some protection in the event of a
building fire where the NAS device is located.
When employing offsite storage, strike a balance between safety and convenience by deciding
how long to keep the media onsite. After the media has been moved offsite, restores will take
much longer because the media is not readily available.
A periodic audit of the offsite facility ensures the media is being stored in secure,
environmentally acceptable conditions, and that it can be located and returned to the facility in
a timely manner.
Server Setup Information Archival
After the administrator has established a regular backup schedule, it is necessary to document
the setup attributes of the NAS device. To maximize the ability to recover from server disasters
and to minimize the time required for recovery, keep current copies of the following
information in a safe location: