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