HELP RECOVER — VMS 5.4
Invokes the RMS Recovery Utility. Applicable only if you have the
RMS Journaling option. See the VAX RMS Journaling Manual.
The RMS Recovery Utility (RECOVER/RMS_FILE) restores RMS files
after the files have become lost or the data in them has become
unusable. You can use RECOVER/RMS_FILE to redo operations (with
after-image journaling, using a previously made backup file), or
to undo operations (with before-image journaling, using the actual
data file).
Format
{ /FORWARD }
RECOVER/RMS_FILE { /BACKWARD} filespec
{ }
Additional information available:
Parameter
filespec Specifies the file to be recovered. Wildcard characters are allowed in the directory specification, file name, file type, and version number fields. If you specify two or more files, separate them with commas. For recovery using after-image journaling, use the backup copy of the data file as the file specification. For recovery using before-image journaling, use the original data file as the file specification. The file specification cannot include a node name, since this command is not valid for network access.
Qualifiers
Additional information available:
/BACKWARD/BEFORE/BI_BUFFER_SIZE/BY_OWNER
/CACHE_SIZE/CREATED/EXCLUDE/FORWARD/JOURNAL/LOG
/MODIFIED/SINCE/UNTIL
/BACKWARD
Rolls a file backward to a previous state. Use the /BACKWARD
qualifier to recover a file using a journal that has before-image
journal entries for the data file that you specify.
To specify a date and time to which the file is to be rolled
backward, use the /UNTIL qualifier. You should always use this
qualifier for before-image recovery; if you do not use the /UNTIL
qualifier when you specify the /BACKWARD qualifier, the file is
automatically rolled back to the time when the first entry was
made in your before-image journal.
The file is rolled back using the before-image journal that was
specified when the file was marked for journaling with the SET
FILE/BI_JOURNAL command. You can override this default by using
the /JOURNAL qualifier.
You must always specify either the /BACKWARD or the /FORWARD
qualifier, but you cannot specify both.
A file marked for both before-image journaling and recovery
unit journaling requires special considerations during before-
image recovery. The data consistency provided by recovery unit
journaling is maintained because DECdtm ensures that transactions
are restored either in their entirety or not at all.
If you use the RECOVER/BACKWARD command to roll back a file that
is also marked for recovery unit journaling, the file is rolled
back and includes modifications for all transactions that were
completed (committed) on or before the ending time of the before-
image recovery, as follows:
o If, at the time when before-image recovery is to end, there are
no active transactions, then before-image recovery takes place
in the same way as when there is no recovery unit journaling.
o If one or more transactions are active at the time before-
image recovery is to end, only those modifications made within
transactions that were completed (committed) on or before the
ending time are included in the file.
For example, suppose you issue the command RECOVER/BACKWARD
/UNTIL=10:30 for a file marked for both before-image and
recovery unit journaling. When before-image recovery is
complete, the rolled-back file will include all modifications
that were made within those transactions that completed on or
before 10:30.
o If you apply before-image recovery to a file that is used in
a multifile application where the files are marked for both
before-image and recovery-unit journaling, then you must use
the /UNTIL qualifier with the RECOVER/BACKWARD command in order
to specify a time to which the file is rolled back. You should
then roll back each of the files in the application to the same
time specified for the first file. If you do not use the same
time value for the /UNTIL qualifier, then the modifications for
one or more transactions may be restored to some of your files,
but not to others.
When the recovery operation is complete, the RMS Recovery Utility
displays the time of the last record which was processed (rolled
back). This is generally the time of the first record modification
after the ending time (as specified with the /UNTIL qualifier);
however, it could be an earlier time if there were one or more
incomplete transactions at the ending time of the before-
image recovery. In this case, modifications made within such
transactions are automatically undone as part of the before-image
recovery operation, and the time of the last record processed
would reflect the first record modified within one of those
transactions.
/BEFORE
/BEFORE[=time]
Selects only those files dated prior to the specified time.
You can specify time as an absolute time, as a combination of
absolute and delta times, or as one of the following keywords:
TODAY (default), TOMORROW, or YESTERDAY. To indicate the time
attribute to be used as the basis for selection, specify one
of the following qualifiers with /BEFORE: /BACKUP, /CREATED
(default), /EXPIRED, or /MODIFIED.
For complete information on specifying time values, see the VMS
DCL Concepts Manual.
/BI_BUFFER_SIZE
/BI_BUFFER_SIZE=blocks
Specifies the number of blocks that RMS recovery reads for each
I/O from the journal. This qualifier is similar in concept to the
multiblock count field (RAB$B_MBC) in RMS. The blocks parameter is
the size of the buffer used to read the before-image journal. The
parameter can take values of 1 to 127 blocks.
Use the /BI_BUFFER_SIZE qualifier to tune your application and
improve performance during recovery. For more information on how
to tune your application using this value, see the Designing
Files/Units of Input/Output section in the Guide to VMS File
Applications and the VMS Record Management Services Manual.
You can use the /BI_BUFFER_SIZE qualifier only when you specify
the /BACKWARD qualifier.
/BY_OWNER
/BY_OWNER[=uic]
Selects only those files whose owner user identification code
(UIC) matches the specified owner UIC. The default UIC is that of
the current process.
Specify the UIC using standard UIC format as described in the VMS
DCL Concepts Manual.
/CACHE_SIZE
/CACHE_SIZE=buckets
Specifies the number of indexed file buckets that are retained
by in-memory cache during a recovery operation. Use the /CACHE_
SIZE qualifier to set the size of a cache in order to improve
performance when recovering indexed files. In general, the
performance of the recovery operation improves as the cache size
grows larger. However, other system considerations could affect
the ideal size.
The /CACHE_SIZE qualifier is similar in concept to the multibuffer
count field (RAB$B_MBF) in RMS. For more information on how to
tune your application using this value, see the Guide to VMS File
Applications and the VMS Record Management Services Manual.
The /CACHE_SIZE qualifier applies only to indexed files. You can
use this qualifier with either /BACKWARD or /FORWARD recovery.
/CREATED
/CREATED (default)
Modifies the time value specified with the /BEFORE or /SINCE
qualifier. The /CREATED qualifier selects files based on their
dates of creation. This qualifier is incompatible with the other
qualifiers that allow you to select files according to time
attributes: /BACKUP, /EXPIRED, and /MODIFIED. If you specify none
of these four time qualifiers, the default is /CREATED.
/EXCLUDE
/EXCLUDE=(file-spec[,...])
Excludes the specified files from the copy operation. You can
include a directory but not a device in the file specification.
Wildcard characters are allowed in the file specification.
However, you cannot use relative version numbers to exclude a
specific version. If you provide only one file specification, you
can omit the parentheses.
/FORWARD
Rolls a file forward from a previous state. Use the /FORWARD
qualifier to recover a backup file by using the after-image
journaling information contained in a journal. Both the journal
and a backup copy of the data file must be available in order to
recover a file using the /FORWARD qualifier.
The re-doing operation starts at the time the most recent backup
was made (assuming that the /RECORD qualifier was used), and the
backup file is rolled forward until the time of the most recent
entry in the journal. You can override the latter value with the
/UNTIL qualifier.
When you use the /FORWARD qualifier, you must use a backup copy of
the original data file as the file specification in your RECOVER
/RMS_FILE command line. You must always specify either /FORWARD or
/BACKWARD, but you cannot specify both.
The file is rolled forward using the after-image journal that was
specified when the file was marked for journaling with the SET
FILE/AI_JOURNAL command. If the after-image journal has been moved
from its original directory, if it has a different file name,
or if it has been restored to disk from magnetic tape, then you
must use the /JOURNAL qualifier to identify the journal. If you
have more than one journal (for example, if you did not use the
BACKUP/RECORD command immediately after creating a new journal),
then you must use a series of as many RECOVER/FORWARD commands as
there are journals. The RMS Recovery Utility automatically knows
which journal to use (unless it has been moved or restored from a
backup copy, in which case you must use the /JOURNAL qualifier),
and it also prompts you to issue a subsequent RECOVER/FORWARD
command by displaying a message indicating that another journal is
to be processed.
When the after-image recovery operation is complete, you must re-
mark the restored file for after-image journaling before it can
be used for further processing using after-image journaling. Re-
marking the file for after-image journaling sets the "journaling
enabled" bit in the file header, which had automatically been
turned off by the Backup Utility when the backup copy was made.
Immediately after re-marking the restored file for after-image
journaling, you should also make a backup copy of it.
When after-image recovery is used for a file that also uses
recovery unit journaling, the RMS Recovery Utility ensures that
the data consistency provided by recovery unit journaling is
maintained. The after-image journal also includes records of
a transaction being started, committed, or aborted. If you use
the RECOVER/FORWARD command to roll forward a file (that is,
the backup copy of a data file) that is also marked for recovery
unit journaling, then the file is rolled forward and includes
modifications for all transactions that were completed (committed)
on or before the ending time of the after-image recovery, as
follows:
o If, at the time when after-image recovery is to end, there are
no active transactions, then after-image recovery takes place
in the same way as when there is no recovery unit journaling.
o If one or more transactions are active at the time after-
image recovery is to end, only those modifications made within
transactions that were completed (committed) on or before the
ending time are applied to the file. For example, suppose
you issue the command RECOVER/FORWARD/UNTIL=10:30 for the
backup copy of a file marked for both after-image and recovery
unit journaling. Then, the restored file will include all
modifications that were made within those transactions that
completed on or before 10:30.
o If your application uses more than one file and you do not
use the /UNTIL qualifier with the first backup copy that you
restore with the RECOVER/FORWARD command, you need only restore
those files in the application that are corrupted or lost.
However, in this case, do not use the /UNTIL qualifier with
any of the files that you restore, in order to maintain data
consistency among all of those files.
If your application uses more than one file and you do use the
/UNTIL qualifier with the first file that you restore with the
RECOVER/FORWARD command, then you must restore every file in
the application, and you must use the /UNTIL qualifier with the
same time value for each file. If you do not use the same time
value for the /UNTIL qualifier, then the modifications for one
or more transactions may be restored to some of your files, but
not to others.
/JOURNAL
/JOURNAL=journal-filespec
Specifies the journal that is to be used for recovery operations.
By default, the RMS Recovery Utility uses the file specification
for the journal that was specified when the data file was marked
for journaling (with the SET FILE/AI_JOURNAL or the SET FILE
/BI_JOURNAL command). To override the default and specify a
different file specification for the same journal, use the
/JOURNAL qualifier. The default file specification for the journal
is filename.RMS$JOURNAL. You can use the /JOURNAL qualifier if the
journal is in a different location from that originally specified
in the SET FILE command (for example, if the original journal
becomes unusable and a backup copy of the journal is on another
volume).
You can only use a journal that contains valid after-image or
before-image data for the specified file.
If you have a series of journals that are to be used in the
recovery operation, and the journals have the same file
specifications as when the SET FILE commands were issued,
then you do not need to use the /JOURNAL qualifier. In this
case, simply use a series of RECOVER commands.
/LOG
/LOG
/NOLOG (default)
Generates a log of the recovery operation. When you use the /LOG
qualifier, the RMS Recovery Utility displays the number of records
that were processed during the recovery operation, and the date
and time of the last record that was processed (recovered).
/MODIFIED
Modifies the time value specified with the /BEFORE or /SINCE qualifier. The /MODIFIED qualifier selects files according to the dates on which they were last modified. This qualifier is incompatible with the other qualifiers that allow you to select files according to time attributes: /BACKUP, /CREATED, and /EXPIRED. If you specify none of these four time modifiers, the default is /CREATED.
/SINCE
/SINCE[=time]
Selects only those files dated after the specified time. You can
specify time as an absolute time, a combination of absolute and
delta times, or as one of the following keywords: TODAY (default),
TOMORROW, or YESTERDAY. Specify one of the following qualifiers
with /BEFORE to indicate the time attribute to be used as the
basis for selection: /BACKUP, /CREATED (default), /EXPIRED, or
/MODIFIED.
For complete information on specifying time values, see the VMS
DCL Concepts Manual.
/UNTIL
/UNTIL=time
Specifies the ending date and time for an after-image or before-
image recovery operation. Specify the date and time using either
absolute time or delta time. See the VMS DCL Concepts Manual for
more information about specifying absolute or delta time.
o For after-image recovery, the /UNTIL qualifier specifies the
date and time up to which the backup copy of the data file is
to be restored. If you do not use the /UNTIL qualifier with
after-image recovery, then all updates through the most recent
update recorded in the after-image journal are restored.
o For before-image recovery, the /UNTIL qualifier specifies the
date and time to which the data file is rolled back. That is,
all modifications to the data file from the present time to the
time specified with the /UNTIL qualifier are removed. In most
cases, you should use the /UNTIL qualifier with before-image
recovery; if you do not, then all modifications recorded in the
before-image journal are removed.
If you are recovering a file that is also marked for recovery unit
journaling, the following rules apply:
o For applications using only one file, if the time specified
with the /UNTIL qualifier (or the most recent modification in
an after-image recovery if /UNTIL is not used) is a point at
which there are no active transactions for the file, then the
file is restored to the time specified by the /UNTIL qualifier.
o If one or more transactions were active at the time specified
by /UNTIL, only those modifications made within transactions
that were completed (committed) on or before that time are
applied to the file. For example, suppose you issue the command
RECOVER/FORWARD/UNTIL=10:30 for the backup copy of a file
marked for both after-image and recovery unit journaling. Then,
the restored file will include all modifications that were made
within those transactions that completed on or before 10:30.
(The same rule applies to before-image recovery: only those
modifications made within transactions that were completed
before the /UNTIL time are included in the restored file.)
o For applications using after-image recovery in which more than
one file is associated with record streams connected to the
same transaction, you should exercise care in choosing whether
or not to use the /UNTIL qualifier. If you do not use the
/UNTIL qualifier with the first backup copy that you restore
with after-image journaling, you need only restore those files
in the application that are corrupted or lost. In this case,
do not use the /UNTIL qualifier with any of the files that you
restore. However, if you do use the /UNTIL qualifier with the
first file that you restore, then you must restore each file in
the application, using the /UNTIL qualifier with the same time
value for each file. If you do not use the same time value for
the /UNTIL qualifier, then the modifications for one or more
transactions may be restored to some of your files, but not to
others.
o For applications using before-image recovery in which more
than one file is associated with record streams connected
to the same transaction, use the /UNTIL qualifier with the
RECOVER/BACKWARD command in order to specify a time to which
the file is rolled back. Then restore each of the files in the
application to the same time specified for the first file,
in order to ensure that the modifications for one or more
transactions are not restored to some of your files, but not to
others.
Examples
1. $ RECOVER/RMS_FILE/BACKWARD/LOG/UNTIL=30-JUN-1990 WEEKLY.DAT
%RMSREC-I-FILBACKWARD, $DISK1:[PAYROLL]WEEKLY.DAT;17 rolled backward
%RMSREC-I-DATETIME, date/time of last record processed:
30-JUN-1990 07:41:23.27
%RMSREC-I-NUMRECS, 936 records processed
This command rolls the file WEEKLY.DAT backwards until 30
June 1990 (default time of day of 00:00). The Recovery Utility
automatically uses the before-image journal that was specified
(or implied) with the most recent SET FILE/BI_JOURNAL command
for the file WEEKLY.DAT. The /LOG qualifier instructs the RMS
Recovery Utility to display the number of records processed
(that is to say, un-done) and the date and time that the last
record was written.
After executing this command, the file WEEKLY.DAT is the same
as it was at midnight, 30 June 1990.
2. $ DIRECTORY/SIZE ACCOUNTS_PAYABLE.RMS$JOURNAL
ACCOUNTS_PAYABLE.RMS$JOURNAL;1 108
$ RECOVER/RMS_FILE/BACKWARD/BI_BUFFER_SIZE=108 ACCOUNTS_PAYABLE.DAT
This example shows that the journal ACCOUNTS_
PAYABLE.RMS$JOURNAL has a size of 108 blocks. The RECOVER/RMS_
FILE/BI_BUFFER=108 command sets the buffer to be 108 blocks.
3. $ RECOVER/FORWARD/UNTIL=30-JUN-1990/LOG WEEKLY_BACKUP.DAT
%RMSREC-I-FILFORWARD, $DISK1:[PAYROLL]WEEKLY_BACKUP.DAT;17 rolled forward
%RMSREC-I-DATETIME, date/time of last record processed:
30-JUN-1990 15:23:44.30
%RMSREC-I-NUMRECS, 2554 records processed
This command rolls the file WEEKLY_BACKUP.DAT forward,
beginning at the time that the file was created by the Backup
Utility. It is rolled forward until 30 June 1990 (using the
default time of day 00:00). Using the /LOG qualifier provides
information about the number of records processed and the date
and time of the last record that was restored. This RECOVER
command assumes the default qualifier /RMS_FILE.
After this operation, the file WEEKLY_BACKUP.DAT is the same as
the data file for which it was the backup copy (WEEKLY.DAT)
at midnight on 30 June 1990. In order to use the restored
file WEEKLY_BACKUP.DAT for further processing in which after-
image journaling will take place, you must re-mark the file for
after-image journaling.
4. $ RECOVER/RMS_FILE/FORWARD/LOG BACKUP.DAT
%RMSREC-I-FILFORWARD, $DISK1:[PAYROLL]BACKUP.DAT;17 rolled forward
%RMSREC-I-DATETIME, date/time of last record processed:
4-AUG-1990 11:28:29.74
%RMSREC-I-NUMRECS, 3490 records processed
This command rolls the file forward, beginning at the point
at which the last backup was made (using the BACKUP/RECORD
command) and continuing through the last record that was
written to the journal. At this point, the recovered file has
the same data as the data file on 4 August at 11:28, with the
file characteristics of the backup file.
5. $ RECOVER/FORWARD/JOURNAL=ARCHIVE_DISK:INVENTORY INVENTORY.BCK
In this example, the after-image journal ARCHIVE_
DISK:INVENTORY.RMS$JOURNAL is applied to the file
INVENTORY.BCK, which is a backup copy of a data file. In this
case, ARCHIVE_DISK:INVENTORY.RMS$JOURNAL might be either a
backup copy of a valid after-image journal, or the original
journal itself which had been moved to a different volume. The
/RMS_FILE qualifier is used by default.