SQL/MX 2.x Database and Application Migration Guide (G06.23+, H06.04+, J06.03+)

Preparing to Migrate From NonStop SQL/MP to
NonStop SQL/MX
HP NonStop SQL/MX Database and Application Migration Guide—540435-005
9-3
Planning for Fallback
multiple databases share the same disk. For minimum disk space requirements for
SQL/MX Release 2.x, see the
SQL/MX Installation and Management Guide. The Disk
Space Analysis Program (DSAP) can help you analyze the use of space on disk
volumes. For more information about DSAP, see the
Guardian Disk and Tape Utilities
Reference Manual.
SQL/MX applications tend to use more memory than SQL/MP applications. If you are
tight on memory, upgrade to more memory. For minimum memory requirements for
NonStop SQL/MX, see the
SQL/MX Installation and Management Guide.
Planning for Fallback
Before you migrate to NonStop SQL/MX, plan for a potential fallback to NonStop
SQL/MP. To ensure that you can fall back more easily, follow these guidelines:
•
Planning New Feature Implementation on page 9-3
•
Keeping SQL/MP Applications, Database Objects, and Metadata on page 9-3
If you encounter a serious problem with NonStop SQL/MX and need to fall back to an
SQL/MP environment, see Section 12, Falling Back to NonStop SQL/MP
.
Planning New Feature Implementation
Before making use of SQL/MX features, make sure that each system node has a
release of NonStop SQL/MX that supports the features that you wish to use. The
simplest approach is to make sure that all relevant nodes have the same release of
NonStop SQL/MX. After you have successfully installed NonStop SQL/MX on all
relevant nodes and verify that it works satisfactorily, begin using the features of
NonStop SQL/MX on those nodes. This strategy effectively separates the installation
phase from the feature development and utilization phase. If fallback becomes
necessary, it is most likely to occur during or shortly after the installation phase, before
you start using new features.
Keeping SQL/MP Applications, Database Objects, and Metadata
If you are migrating to SQL/MX Release 2.x from an SQL/MP database environment,
do not delete the SQL/MP applications, database objects, and metadata until you are
sure you do not need to fall back. Deleting these objects prevents a successful
fallback.
Keep source files of SQL/MP applications and the compiled executables in a safe
place. Do not delete them.
Note. If you encounter the problem when using new features that are specific to NonStop
SQL/MX, consider discontinuing the use of those features instead of falling back.