HP 3000 Manuals HP 3000 Manuals
Maintaining a Backup Library
Establish a library for storing backup media and backup records. Include
the following in your library:
* A large stock of new or scratch media to use for backups.
(Scratch media are used media containing information that is no
longer needed.)
* A record of each tape's (or other media) contents. It should be
easy to find the backup media needed to restore the system in the
event of a failure.
* Your actual backup media.
Maintaining a Large Stock Of Backup Media
You need to maintain a large and easily accessible stock of available
backup media, because you can never be sure ahead of time exactly how
many units of backup media you need for each backup. The number of units
you need depends upon whether you are performing a full or a partial
backup and how much data is stored on your system.
Using new units of backup media ensures the best possible data integrity.
You can, of course, safely reuse backup media if they are in good
condition and if they contain outdated information. The information on
used backup media is outdated when the purge date on the label has
passed.
To help judge whether a used tape is in good condition, you can use the
cycle field of the Hewlett-Packard standard sticky tape label to track
the number of times a tape has been used. Tapes wear out and become
unreliable after being used many times. To determine whether a tape is
still usable, consult the manufacturer's recommendations.
When using labeled media, the expiration date in the label can be used to
recycle media.
Keeping Backup Records
Each time you create a backup, have the system print a report describing
the backup unit's contents with the SHOW=OFFLINE option. For example:
:FILE T;DEV=TAPE
:STORE @.OPERATOR.SYS;*T;SHOW=OFFLINE
File these reports in a special filing cabinet or attach them directly to
the appropriate tape reel (or other media). Label each item according to
the instructions provided in Chapter 3, "Preparing Storage Devices."
Storage of Backup Media
Backup media may be the only copy of current or previous information
stored from your system. When you need to restore information from
backup media, you should be able to easily find the item you need. Your
library enables you to maintain complete copies of your system's data,
and an easy method for locating the data you want to recover.
There are two reasons you should always keep older backup data in
addition to your current backup data: in case the most recent copies are
bad, and for restoring older files that may have been removed from the
system some time ago. In such situations, you can restore files from the
most recent intact copy.
To set up a library, perform the following steps:
* Obtain a substantial number of backup media. The exact number you
need depends on how much data you will be storing and how long the
backup data will be retained.
* Obtain a container such as a vault, a metal cabinet, or rack in
which to keep the backup data.
* Establish a control program for maintaining backup data for a
specified length of time.
* Establish a cleaning and verifying schedule for the media devices.
* As part of your disaster recovery plan, create a duplicate library
in a safe, offsite location. Refer to Chapter 12, "Disaster
Recovery," for more information.