HP RMS Journaling for OpenVMS
HP RMS Journaling for OpenVMS SPD 27.58.16
No user intervention is required to roll back a recovery
unit that is incomplete. The rollback of an incomplete
transaction is started and completed automatically the
next time a user attempts to access the file.
Interaction with the Backup Utility
To recover data using AI journaling, a backup copy of the
file must be available. This copy must be made with the
Backup utility (BACKUP); a copy of the file made with
the COPY or CONVERT command cannot be used. The
backup copy of the file must be made after you enter the
SET FILE/AI_JOURNAL command but before opening
the file for update. BACKUP requires exclusive access
to files being backed up. No user or application program
can access the file until the backup is finished.
HP recommends the use of BACKUP/RECORD. If the
file is then rolled forward, the modifications that have
been made since the most recent backup are applied.
If a backup copy of a file is rolled forward with the RMS
Recovery utility, you must remark the file for AI jour-
naling with the SET FILE/AI_JOURNAL command. You
must make a backup copy of that file after marking it
for AI journaling and before application updates are al-
lowed.
A backup copy of the file must be remarked for journal-
ing if it is to be used in place of the original file.
Interaction with Volume Shadowing for OpenVMS
Volume Shadowing for OpenVMS can be used in con-
junction with AI journaling. AI journaling helps recover
data in the following cases not addressed by Volume
Shadowing for OpenVMS:
• Mistaken deletion of a file by a system user or
operator
• Corruption of the file system pointers
• RMS file corruption due to a software error or incom-
plete bucket write operations to an indexed file
Failures Not Addressed by RMS AI Journaling
In the case of either a process deletion or system fail-
ure, an update can be written to the AI journal file, but
not make it to the data file. If only AI journaling is in use,
the data file and journal are not automatically made con-
sistent. If additional updates are made to the data file
and are recorded in the AI journal, a subsequent man-
ual roll forward operation could produce an inconsistent
data file.
If you use RMS RU journaling in combination with AI
journaling, the automatic transaction recovery restores
consistency between the AI journal and the data file.
Under some circumstances, an application that uses
only AI journaling can take proactive measures to guard
against data inconsistencies after process deletions or
system failures. For example, a manual roll forward
of AI-journaled files ensures consistency after a system
failure involving either an unshared AI application (sin-
gle accessor) or a shared AI application executing on a
standalone system.
However, in a shared AI application, there may be noth-
ing to prevent further operations being executed against
a data file that is out of synchronization with the AI jour-
nal file after a process deletion or system failure in a
cluster. Under these circumstances, consistency among
the data file(s) and the AI journal file can be provided
by using a combination of AI and RU journaling.
Failures Not Addressed by RMS Recovery Unit
Journaling
RU journaling alone does not provide recovery when
a multiblock bucket write operation to an indexed
file is in progress, leaving the bucket in the in-
dexed file in a corrupt state. Use AI journal-
ing in conjunction with RU journaling to recover
from the following failed multiblock bucket write
operations:
• Failure of the Integrity server, Alpha, or VAX host
during a multiblock write operation, such as a system
failure, halt, power failure, or system shutdown.
• Permanent loss of path to the disk during a multiblock
write operation.
• Cancellation of a multiblock write operation in
progress. This operation is possible only with disks
that use the DUDRIVER or that access a disk drive
through the MSCP server. Other disk drives ignore
the cancellation of I/O and are not affected.
HARDWARE REQUIREMENTS
Refer to the HP OpenVMS Operating System for Al-
pha Version 7.3-1 and 7.3-2 and VAX Version 7.3 Soft-
ware Product Description (SPD 25.01.xx) or the HP
OpenVMS for Alpha and Integrity Servers Version 8.3
Software Product Description (SPD 82.35.xx), and the
OpenVMS Cluster Software Software Product Descrip-
tion (SPD 29.78.xx) for hardware requirements and sup-
ported processors.
OpenVMS CLUSTER ENVIRONMENT
This layered product is fully supported without restric-
tions when installed on any valid and licensed Open-
VMS Cluster* configuration. The Hardware Require-
ments section of this product’s SPD and the HP Open-
VMS Operating System for Alpha Version 7.3-1 and 7.3-
2 and VAX Version 7.3 Software Product Description
3