DSAs on Tru64 UNIX systems support arguments to the CREATE DSA
directive. The arguments are as follows:
Syntax:
CREATE DSA [FROM MEMORY IMAGE | FROM SNAPSHOT]
If you use the FROM MEMORY IMAGE argument, the DSA attempts to
read a memory image file, and returns a DSA Information Tree
Corrupt error if none is available. The DSA does not attempt
to read a snapshot file or create a new database. If the DSA
can find a valid memory image file, it returns a message
indicating that is has successfully read the memory image file.
The memory image file contains a copy of the schema. This means
that the DSA does not read the schema during creation. However,
the DSA displays a warning message if its copy of the schema
is not the same as the schema file. If the schema has been
changed, use the following commands to force the DSA to read it:
> DELETE DSA TO SNAPSHOT
> CREATE DSA FROM SNAPSHOT
If you use the FROM SNAPSHOT argument, the DSA attempts to read
a snapshot file, as in previous versions, and returns a DSA
Information Tree Corrupt error if none is available. The DSA does
not attempt to read a memory image file or create a new database.
If the DSA can find a valid snapshot file, it returns a message
indicating that is has successfully read the snapshot file.
Do not use the FROM SNAPSHOT argument unless a management
tasks specifically requires it. A snapshot file is
significantly less efficient than a memory image file, and if
you create a snapshot file that is more recent than a memory
image file, you invalidate the memory image file. The FROM
SNAPSHOT argument is supported for a small number of management
tasks only. Forcing the DSA to read a new schema is one of those
tasks.