HP 3000 Manuals HP 3000 Manuals
Determining Your Backup Strategy
The TurboSTORE programs allow you to store files to a single device or to
multiple devices.
The best way to use your backup devices depends upon the characteristics
of the files that you are storing, your needs for compatibility with
other versions of MPE, and your system configuration.
The characteristics of the set of files help determine choices (or
options) for storing them. Use the following guidelines to select the
most appropriate method:
* How many files do you need to back up?
Generally, the more files in the fileset, it is to your advantage
to use multiple devices or a high capacity storage device such as
a magneto-optical disk device.
* If you are storing only a few files of moderate size, one
backup device such as a tape drive or DDS-format device is
sufficient.
* If you are storing many files (for example, all the files
in an account, or a smaller number of very large files), a
multiple-device backup or single magneto-optical device is
best.
* If you need to do small, fast application backups, you may
want to use the store-to-disk feature of TurboSTORE/iX 7x24
True-Online Backup (B5152AA). This allows you to quickly
backup key applications to disk files.
* Do the backup files need to be compatible with another system?
Compatibility with other versions of MPE limits your choices. If
you need to create STORE tapes that are compatible with MPE V/E,
you must use the TRANSPORT option. This restricts you to a subset
of the available STORE commands, and allows you to only store to
one device. If you need to take files from a MPE/iX 5.0 or later
system to a pre-5.0 system, you should use the TRANSPORT=MPEXL
option. This ensures that various POSIX features are correctly
translated to a pre-POSIX version of MPE.
* Does your system configuration include multiple backup devices?
If you do not need to create backups compatible with older
versions of MPE, then your system configuration is the most
important determining factor of which multiple-device method to
use. Use the following guidelines to select a method:
* Which and how many backup devices do you have?
If you have two or three like backup devices, use either
parallel or sequential devices. If you have at least four
devices, use two or more parallel device pools.
* Do you intend to use labeled tapes?
Labeled tapes can be used with a single device and parallel
devices, but not with sequential devices. Unlabeled tapes
can be used with single, parallel, and sequential devices.
Magneto-optical devices cannot be used to perform labeled
backups.
* Do you have user volumesets or mirrored volume sets on your
system?
If you use volume sets for application and volume management, then
you may want to use the ONVS option of STORE. This option allows
you to back up all files on a particular volumeset, including the
system directory information for the volumeset. Doing backups on
a volumeset basis can help reduce downtime by breaking up a large
backup into individual volumeset backups. Recovery time is also
increased, since you can restore from backups that only contain
files for a particular volumeset.
If you are using mirrored disks, and you do not have the
TurboSTORE/iX 7x24 True-Online Backup product, you can use the
SPLITVS option of STORE to back up a split copy of your mirrored
set.
However, if you are using TurboSTORE/iX 7x24 True-Online Backup,
the recommended way of performing mirrored disk backups is to use
either the ONLINE=START or ONLINE=END option. TurboSTORE/iX 7x24
True-Online Backup allows you to back up your volumeset without
losing the protection of the mirrored disks, and without closing
down files.
* Do you have critical applications that need to be available 24
hours a day?
If your system environment includes applications that need to be
available on a 24-hour basis, you should use TurboSTORE/iX 7x24
True-Online Backup. This product provides three different online
backup options:
* ONLINE, which requires files to be closed at the start of
the backup.
* ONLINE=START or ONLINE-END, which allow files and
applications to remain open throughout the entire backup.
Using any of the online backup options means that you do not have
to dedicate the system to doing backups. Using the new 7x24
True-Online backup option allows you to backup files and
applications while users are accessing them. Using the normal
online option requires files being backed up to be closed for a
short time at the start of the backup. Normal access can be
resumed once the actual backup begins.
The TurboSTORE/iX 7x24 True-Online Backup options allow you to
schedule the sync point for the backup at either the beginning of
the backup (ONLINE=START) or at the end of the backup
(ONLINE=END). The backup's sync point is the point when the state
of all files being backed up is synchronized. When the backup is
restored, all files are restored to the state they were in at the
time of the sync point. TurboSTORE also synchronizes any
TurboIMAGE or ALLBASE/SQL databases being stored, ensuring that
consistent copies of the databases are written to the backup.
See Chapter 7 for more information on using the new TurboSTORE/iX
7x24 True-Online Backup feature.