AIX Storage Management

Appendix B. Higher Level Storage Management Products

This appendix is intended to provide an overview of some of the higher level

storage management products available. The products will be compared in

terms of function and positioning.

The main areas in which higher level tools provide enhanced function are:

1. Automation

The provision of mechanisms to define when information should be backed

up, archived or migrated, and what information should be selected. This

allows the defined operations to be scheduled as required without the need

for operator intervention.

2. Backup/restore

The ability to create copies of a client system′s vital data, so that in the

event of a failure, the client can be restored to the same state that it was at

the time of the last backup.

3. Archive/retrieve

The ability to free up space at the client system by moving or archiving

infrequently accessed information from the client to the archive storage

space (usually at a server machine). If the information is required again, it

can be retrieved from the archive.

4. Migration

The ability to structure the storage subsystems in such a way that elements

of the subsystem are used in the most efficient fashion. For example,

frequently accessed information, or information requiring high performance

access should be stored in fast storage (usually disk). Information that is

less frequently accessed should be moved to less expensive, lower

performance, higher capacity media such as optical; this should happen

automatically if possible, thereby freeing up space in the much in demand

fast storage. If the second level of storage (that used by the first movement,

or migration) of information becomes full, or for information that is accessed

even more rarely, a third level could be defined of even higher capacity,

cheaper, slower media, such as tape.

Levels in the hierarchy should also be accessible for specific purposes; for

example, backups, or long term archives would be best stored in the tape

level.

5. Disk space utilization

A mechanism by which disk space on a client can be utilized more

efficiently. This is usually implemented by using the client disk as a cache,

and maintaining the full information space at a server. When data is

requested by an application on the client, it can be transparently copied to

the client cache - clients see the cache to be as large as the information

space at the server.

This can be used in conjunction with the capabilities mentioned in the

previous points. The server information space can be treated as a level in a

storage hierarchy, thereby increasing efficiency further. The space can also

be backed up more easily.

6. Central management

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