Requires read (R), write (W), and control access. Being the owner
of the file is one way to get control access.
Marks one or more RMS files for after-image journaling. You can
also specify certain characteristics of the journal with this
command, including its file specification, whether it is to be
created, its initial size, and its default extension quantity.
The SET FILE/NOAI_JOURNAL command unmarks a file for after-image
journaling.
The SET FILE command is not supported for remote files. You
must use the SET FILE command from the system where the file
is located.
For more information, see the RMS Journaling documentation.
Format
SET FILE/[NO]AI_JOURNAL=(FILE=journal-filespec[,...])
data-filespec[,...]
1 – Parameter
data-filespec[,...]
Identifies the file to be marked for after-image journaling. If
you specify more than one file, separate the file specifications
with commas. The asterisk (*) and the percent sign (%) wildcard
characters are allowed. The file specification cannot include a
node name, since the SET FILE command is not valid for network
access.
2 – Description
The SET FILE/AI_JOURNAL command marks one or more RMS files
for after-image journaling. You can also specify certain
characteristics of the journal with this command, including its
file specification, whether it is to be created, its initial
size, and its default extension quantity. The SET FILE/NOAI_
JOURNAL command unmarks a file for after-image journaling. After
a data file is marked for after-image journaling with the SET
FILE/AI_JOURNAL command, the following events occur whenever the
file is opened by RMS for write operations:
o The journal is opened.
o All subsequent modifications to the data file are recorded in
the journal.
NOTE
To be able to recover the data file at a later time,
you must make a backup copy of the data file, even if it
contains no data.
You must use the FILE keyword to specify a journal. By default,
any portions of the file specification that you omit will be the
same as the data file that is to be journaled, but with the file
type RMS$JOURNAL. That is, if you issue the following command,
then, by default, the file specification for the after-image
journal is JOURNAL_DISK:PAYROLL.RMS$JOURNAL:
$ SET FILE/AI_JOURNAL=(FILE=JOURNAL_DISK:) FINANCE_DISK:PAYROLL.DAT
You should always keep the journal for after-image applications
on a different volume from that of your data file. If recovery
becomes necessary, you will be able to perform after-image
recovery only if a backup copy of the data file is available.
Use the FILE keyword to specify the journal location.
Use the SET FILE/NOAI_JOURNAL command to unmark a file for after-
image journaling. After you use the SET FILE/NOAI_JOURNAL command
for a file, modifications to that data file will no longer be
written to the journal.
You must use the SET FILE/NOAI_JOURNAL command before you can
delete a file that has been marked for after-image journaling.
3 – Keywords
Four keywords are used as parameters to the SET FILE/AI_JOURNAL
command: ALLOCATION, [NO]CREATE, EXTENSION, and FILE. You must
always use the FILE keyword; you can also use any, all, or none
of the other three keywords.
Use an equal sign (=) immediately after the SET FILE/AI_JOURNAL
command to use a keyword. If you use more than one of the
keywords, enclose the list in parentheses and separate the items
in the list with commas.
ALLOCATION=n
Specifies the initial size, in blocks, of the journal. The
ALLOCATION keyword is meaningful only when the CREATE keyword
is also used.
The default allocation is 0 blocks.
CREATE
Specifies that a new journal is to be created. If no journal
exists, using this keyword creates a new one. If a journal (with
the file specification given in this command) already exists,
using this keyword creates a new version of the journal. In the
latter instance, the data file named in this SET FILE command
is journaled to the new journal. Any other files that are being
journaled to the previous version of the journal will continue to
be journaled to that previous version.
If a journal does not already exist, be sure to use the CREATE
keyword with the SET FILE/AI_JOURNAL command. If you do not
specify the CREATE keyword and the file that you specify with
the FILE keyword does not exist, a journal will not automatically
be created and an error message is displayed.
When you create a journal for after-image journaling, the file
protection for the journal is determined as follows:
o If a version of the journal that you specify with the CREATE
keyword already exists, then the new version of the journal
has the same file protection and access control list (ACL) as
the most recent version.
o If there is no existing journal (that is, if you are creating
version 1 of the journal), then the file protection and
ACL of the journal are the default file protection for the
process that creates the journal, except that none of the four
ownership categories (system, owner, group, world) is given
delete access.
Also, every time that you use the CREATE keyword, be sure to make
a backup copy of the data file. (If it is the first time that
the data file is marked for after-image journaling, then you must
make a backup copy of the data file, regardless of whether the
CREATE keyword is used.)
NOTE
To be able to recover the data file at a later time, you
must mark the file for journaling, and then make a backup
copy of the data file, even if it contains no data.
In most cases (in particular, when you are using after-image
journaling to protect against loss of data from a device
failure), you should keep the backup copy on a different volume
from the data file. If recovery becomes necessary, you will be
able to perform after-image recovery only if a backup copy of the
data file is available.
If you want to use a single journal for both after-image and
before-image journaling, do not use the CREATE keyword with both
the /AI_JOURNAL and /BI_JOURNAL qualifiers, because that will
create two separate journals. When you create a journal that
will be used for more than one data file or more than one type
of journaling (after-image or before-image), you should first
use a SET FILE command to create the journal for a single type
of journaling and for a single data file. After the journal is
created, then you can use a single SET FILE command for multiple
data files and both after-image and before-image journaling. For
example, you might use the following sequence of commands:
$ SET FILE/AI_JOURNAL=(FILE=JNL_DISK:,CREATE) [WEEKLY]SALES.DAT
$ SET FILE/BI_JOURNAL=(FILE=JNL_DISK:[WEEKLY]SALES) -
_$INVOICES.DAT,COMMISSIONS.DAT
EXTENSION=n
Specifies the default extension quantity, in blocks, for the
journal. You can specify a value from 0 to 65,535.
The EXTENSION keyword is meaningful only when you use the CREATE
keyword. If the file is extended, the value that you specify is
used. If you do not use the EXTENSION keyword when you create a
journal, RMS calculates its own EXTENSION value for the journal.
FILE=journal-filespec
Specifies the journal where all modifications to the named data
file will be recorded. The default file specification for the
journal is the file specification of the data file that you name,
but with a file type of RMS$JOURNAL. If you provide a partial
file specification for the journal, any unspecified portions are
taken from the default file specification. The FILE keyword is
required when you use the SET FILE/AI_JOURNAL command.
If you are using after-image journaling to protect against the
loss of data due to a device failure (such as a head crash),
you should keep the journal on a different volume from the
one on which the data file is kept. Only by keeping the data
file and journals on separate volumes can you use after-image
recovery to restore the data file if its recording medium becomes
corrupted (for example, by a disk head crash). If you issue the
SET FILE/AI_JOURNAL command and the journal is on the same volume
as the data file being marked for after-image journaling, the
INVAIJDEV warning message is issued.
The file specification cannot include a node name, since the SET
FILE command is not valid for network access.
You can use a single journal for multiple data files for after-
image journaling, and you can also use a single journal for both
after-image and before-image journaling.
4 – Qualifier
4.1 /LOG
/LOG
/NOLOG (default)
Controls whether the SET FILE command displays the file
specification and the type of journaling that has been set. By
default, this information is not displayed.
5 – EXAMPLES
1.$ SET FILE /AI_JOURNAL=(FILE=JOURNAL_DISK:,CREATE) -
_$FINANCE_DISK:[PAYROLL]WEEKLY.DAT
In this example, the file FINANCE_DISK:[PAYROLL]WEEKLY.DAT is
marked for after-image journaling. The required FILE keyword
is used to place the journal on the disk JOURNAL_DISK, and
the CREATE keyword generates a new version of the journal.
The file specification for the journal will be JOURNAL_
DISK:[PAYROLL]WEEKLY.RMS$JOURNAL.
The next step in the after-image journaling process after
issuing this command is to back up the data file.
2.$ SET FILE/AI_JOURNAL=(FILE=JOURNAL_DISK:,CREATE)/LOG SALES.DAT
%SET-I-JCREATED, journal JOURNAL_DISK:[REGION_1]SALES.RMS$JOURNAL;1
created
%SET-I-FILMARKAI, FINANCE_DISK:[REGION_1]SALES.DAT;1 marked for RMS
after-image journaling
-SET-I-JFILE, using journal JOURNAL_DISK:[REGION_1]SALES.RMS$JOURNAL;1
%SET-I-MODIFIED, FINANCE_DISK:[REGION_1]SALES.DAT;1 modified
In this example, the file SALES.DAT in default directory
FINANCE_DISK:[REGION_1] is marked for after-image journaling
and the /LOG qualifier causes the result of the SET FILE
command to be displayed on the terminal.
3.$ SET FILE/AI_JOURNAL=(FILE=JNL_DISK:,CREATE)/LOG OVERDUE.DAT
%SET-I-JCREATED, journal JNL_DISK:[PAYABLE]OVERDUE.RMS$JOURNAL;1
created
%SET-I-FILMARKAI, WORK_DISK:[PAYABLE]OVERDUE.DAT;1 marked for RMS
after-image journaling
-SET-I-JFILE, using journal JNL_DISK:[PAYABLE]OVERDUE.RMS$JOURNAL;1
%SET-I-MODIFIED, WORK_DISK:[PAYABLE]OVERDUE.DAT;1 modified
$ SET FILE/BI_JOURNAL=(FILE=JNL_DISK:)/RU_JOURNAL/LOG OVERDUE.DAT
%SET-I-FILMARKBI, WORK_DISK:[PAYABLE]OVERDUE.DAT;1 marked for RMS
before-image journaling
-SET-I-JFILE, using journal JNL_DISK:[PAYABLE]OVERDUE.RMS$JOURNAL;1
%SET-I-FILMARKRU, WORK_DISK:[PAYABLE]OVERDUE.DAT;1 marked for RMS
recovery-unit journaling
%SET-I-MODIFIED, WORK_DISK:[PAYABLE]OVERDUE.DAT;1 modified
In this example, the file OVERDUE.DAT is marked for all three
types of journaling using two SET FILE commands. A single
journal (JNL_DISK:[PAYABLE]OVERDUE.RMS$JOURNAL) will be used
for after-image and before-image journaling.
The first SET FILE command uses the /CREATE
qualifier to create a new after-image journal,
JNL_DISK:[PAYABLE]OVERDUE.RMS$JOURNAL. The file specification
uses the current default directory [PAYABLE] and the default
file extension RMS$JOURNAL.
The second SET FILE command checks the disk JNL_DISK to see
whether a journal already exists, and uses the existing journal
for before-image journaling, as well as after-image journaling.
4.$ SET FILE/NOAI_JOURNAL/NOBI_JOURNAL -
_$ WORK_DISK:[PAYABLE]OVERDUE.DAT,VENDORS.DAT
In this example, the files OVERDUE.DAT and VENDORS.DAT are
unmarked for both after-image and before-image journaling. It
is not necessary to specify the journals that were used. If
more than one journaling type was applied to the data files
(as in the previous example), then you must cancel each of the
journaling types before you can delete the data files.
5.$ SET FILE/AI_JOURNAL=(FILE=JOURNAL_DISK,CREATE)-
_$ /RU_JOURNAL [FIELD]SALARY.DAT
$ SET FILE/AI_JOURNAL=(FILE=JOURNAL_DISK:[FIELD]SALARY)-
_$ /RU_JOURNAL CHECKS.DAT
In this example, the files SALARY.DAT and CHECKS.DAT are both
marked for after-image and for recovery unit journaling. The
after-image journaling for both files is written to the same
journal, JOURNAL_DISK:[FIELD]SALARY.RMS$JOURNAL.