HP 3000 Manuals

STORE and TurboSTORE/iX Products Manual

Scheduling Backups 

There are two important considerations when planning a backup schedule:

   *   Plan full and partial backups to efficiently duplicate the most
       recent system information.

   *   Schedule a regular time for performing backups.

Full and Partial Backups 

There are two ways to perform a system backup.  A full backup copies all
files stored in your system whether or not any of the information in them
has changed since the last backup.  A partial, or incremental, backup
copies only the files that have changed since the last full backup.  This
can be done with the DATE parameter of the STORE command.  A well-planned
backup schedule combines both methods.  It usually calls for a full
backup once a week and a partial backup each remaining workday.  If you
follow such a schedule, you would lose no more than 24 hours worth of
information should the system experience problems.

Your requirements for recovery time should also be considered.  Although
it takes less time to make partial backups of your data between full
backups, it also takes longer to restore them, should you need to.  When
restoring from partial backups, the last complete full backup must be
restored first.  Then, each subsequent partial backup must be restored.
This is in contrast to spending more time each night on a full backup,
but only needing to restore files once.  You should examine your recovery
time needs and expectations before deciding on a backup strategy.

Figure 2-1  shows a sample backup schedule that combines both full and
partial system backups.


          Figure 2-1.  Sample Backup 

Selecting a Time for Backups 

It is best to perform backups at a time when people are not normally
using the system.  Often, system administrators choose to perform backups
at the close of the workday or later in the evening.  It is also a good
idea to schedule the backup for the same time every day so users know
when to expect it and can plan ahead.

Be sure to schedule enough time for each backup.  Full backups take more
time and more media than partial backups.  Performing a partial backup a
day or so after a full backup takes less time and less backup media than
a partial backup performed almost a week later.

As the week progresses, users will have modified or added more files
since the last full backup, and more new information must be duplicated.
If you perform a full backup on Friday, the first partial backup on
Monday may take only one tape, for example, and not much time.  By
Thursday, however, the day before the next scheduled full backup, a
partial backup requires several tapes, for example, and considerably more
time, but still less than a full backup.

The TurboSTORE/iX 7x24 True-Online Backup ONLINE option allows you to
back up critical data and applications that need to be available at all
times.  Using just the ONLINE option allows users to access files after a
short period of inaccessibility at the beginning of the backup.  However,
using the new ONLINE=START or ONLINE=END options, users can continue to
access files, uninterrupted, throughout the backup.

Refer to Chapter 6, "STORE and TurboSTORE Command Options," for
information on using the ONLINE option only, or Chapter 7, "TurboSTORE/iX
7x24 True-Online Backup," for information on using the new ONLINE=START
and ONLINE=END options.

MPE/iX 5.5 Documentation