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 |
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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 you will need for each backup. The amount of media you will need
depends on how much data is being stored, and what STORE and TurboSTORE
options, such as data compression, are being used. The amount of data
on your system, and whether you are doing a full or partial backup also
greatly influence the amount of backup media required.
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good condition and if they contain outdated information.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information on used backup media is outdated when the purge date on the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 |
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Each time you create a backup, have STORE display a listing describing
what files were stored on each piece of media. STORE's SHOW=OFFLINE
option sends this listing, by default, to the line printer. For example:
:FILE T;DEV=TAPE
:STORE @.OPERATOR.SYS;*T;SHOW=OFFLINE
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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 |
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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 13, "Disaster Recovery,"
for more information.
