HP 3000 Manuals HP 3000 Manuals
Choosing Full or Partial Recovery Procedures
ALLBASE/SQL also provides the capability to restore all the files in the
DBEnvironment (full recovery) or to restore only a subset of the files in
the DBEnvironment (partial recovery).
You may choose full or partial recovery when using either nonarchive or
archive mode logging. If a crash occurs in a DBEnvironment that is
contained solely on one drive, you must do a full recovery of the entire
DBE (or that portion of the DBEnvironment that you stored because it was
essential data).
If a crash occurs to a DBE that is spread across several drives,
regardless of whether you are using nonarchive or archive logging, the
kind of recovery you must do depends on certain operating system
conditions and on which ALLBASE/SQL files were destroyed in the crash.
The failure conditions on the operating system must be such that you are
able to restore only those files that were located on the device that
failed. Your failure conditions may require you to restore files on
several or all drives associated with your DBEnvironment. If you must
restore files on several or all devices, partial recovery is not useful.
See your system administrator for details for your operating system. Be
sure that your disaster recovery plan includes the operating system
considerations needed for recovery of your DBEnvironment, not just the
ALLBASE/SQL considerations.
You must do a full recovery if any of the following files were destroyed
in the crash:
* Any of the SYSTEM DBEFiles (DBEFile0 or any files you added to the
SYSTEM DBEFileSet) and/or the DBEConFile which is stored on the
same drive as the SYSTEM DBEFiles.
* In the case of single logging, your single log file; unless, in
the case of archive logging, the file has never been used, or you
have already stored the log file off, and the file has not yet
been reused. (If you are using dual logging, the loss of one leg
of the log does not require you to restore the DBEnvironment.
Just repair the damaged device and create a new set of log files
to restore dual logging.)
If the crash destroyed any other files than those listed above, you can
repair the damaged drive and then do a partial recovery which only
includes the files that were damaged in the crash. While the damaged
drive is out of operation, you can still operate the remainder of the
DBEnvironment so long as the operating system permits and so long as
users only access the DBEFiles on the undamaged drives. Any attempt to
access files on the damaged drives will result in the generation of an
error message.