Availability options are a complement to a good save strategy,
not a replacement.
Availability options can significantly reduce the time it takes you to
recover after a failure. In some cases, availability options can prevent
you from having to perform a recovery.
To justify the cost of using availability options, you need to understand
the following items:
- The value your system provides.
- The cost of a scheduled or unscheduled outage.
- What your availability requirements are.
The following list shows the availability options that you can use to complement
your save strategy:
- Journal management lets you recover the changes to objects that have occurred
since your last complete save.
- Access path protection lets you re-create the order in which records in
a database file are processed.
- Disk pools limit the amount of data you need to recover to the data in
the disk pool with the failed unit.
- Device parity protection enables you to reconstruct data that is lost;
the system can continue to run while the data is being reconstructed.
- Mirrored protection helps you keep your data available because you have
two copies of the data on two separate disk units.
- Clustering lets you maintain some or all data on two systems; the secondary
system can take over critical application programs if the primary system fails.
The Availability roadmap for your iSeries™ topic contains information that
you can use to implement an availability solution on your iSeries server.