Document revision date: 15 July 2002

An incompatibility between the operating procedures of the PATHWORKS for OpenVMS Macintosh server and OpenVMS incremental backup operations can cause BACKUP to save entire disks or directory structures, including subdirectories and files.

BACKUP can detect whether a directory file has been modified since the date indicated by the Backup Date field in the file header. If a directory file has been modified, all subdirectories and files of that directory are saved for possible later restore operations.

Updating the modification date of directory files is unusual for OpenVMS systems. However, it can happen if, for example, you rename a directory file from one location to another. In contrast, the PATHWORKS Macintosh server maintains the modification date of directory files for Macintosh users; that is, it updates the modification date for each directory change, file creation, and file deletion.

Thus, an incremental backup of a disk where PATHWORKS is used to serve files to Macintosh users may result in saving the entire disk or entire directories (including their subdirectories and files) instead of just the user files that were created or modified since the last incremental backup operation.

You can avoid saving files unnecessarily in either of the following ways:

• By using the /NOINCREMENTAL qualifier.
  On a save operation, you can use the BACKUP qualifier /NOINCREMENTAL to avoid saving all the files and subdirectories under directories that have been modified. (Some files will, however, still be saved.) Use this qualifier only if you are sure that you do not want to save all data.
  Prior to OpenVMS Version 6.2, the system, by default, did not save the files and subdirectories that were under directories that had been modified. In OpenVMS Versions 7.0 and 7.1, to ensure a successful restore, the system saved all files and subdirectories under directories that had been modified. This behavior, however, sometimes resulted in saving files and subdirectories that were not needed for later restore operations. The /NOINCREMENTAL qualifier allows you more control over the amount of file data that is saved.
• By performing a "dummy" BACKUP/RECORD operation on all directory files immediately before performing the incremental backup. For example:

  $ BACKUP/RECORD/IGNORE=(INTERLOCK) - _$ disk:[000000...]*.DIR;* - _$ NLA0:DUMMY.BCK/SAVE/NOCRC/GROUP_SIZE=0 $ $ BACKUP/VERIFY/FAST/RECORD/IGNORE=(INTERLOCK) - _$ /NOASSIST/COMMENT="Incremental backup of DISK:" - _$ disk:[000000...]*.*;*/SINCE=BACKUP - _$ tape:incr.bck/LABEL=incr/SAVE

  
  In this example, the first BACKUP command performs the dummy backup operation, and the second command performs the actual incremental backup. The first command updates the Backup Date field for all the directory files. Specifying the null output device NLA0:[000000...] causes a save set file not to be written. Because no file information needs to be retained from this operation, the /NOCRC and /GROUP_SIZE=0 qualifiers are specified to avoid CRC and XOR block calculation.

On a standalone workstation, you are probably responsible for backing up files on your user disks. Section 11.15.7.1, Section 11.15.7.2, and Section 11.15.7.3 contain command procedures for making image, incremental, and interactive backups of user disks on your workstation.

Compaq also provides two template command procedures in the SYS$EXAMPLES directory for you to use in designing BACKUP command procedures. These command procedures are called BACKUSER.COM and RESTUSER.COM.

If you are not familiar with using command procedures, refer to the OpenVMS User's Manual.

11.15.7.1 Using a Command Procedure for Nightly Image Backups

The following command procedure performs nightly image backups, backing up all the files on disk DUA2: to a tape in MUA0. The files are copied to a magnetic tape save set named FULL_BACKUP.SAV. This procedure is particularly useful for backing up files on a MicroVAX system or workstation.

How to Perform This Task

To use the command procedure, perform the following steps:

1. Ensure that you have a batch queue available on your system. (See Section 14.3 for information about setting up a batch queues.) You submit the command procedure only once, and it will execute daily at 2:00 A.M. The command procedure automatically resubmits itself at 2:00 each morning; however, you must physically load a tape each day or the backup procedure will fail. Even if the backup procedure fails, however, the command procedure will continue to resubmit itself.
2. From the SYS$MANAGER directory, create the command procedure as shown and call it SYSTEM_BACKUP.COM.

   $! $! Resubmit this procedure -- $ SUBMIT/AFTER="TOMORROW+2:0" SYS$MANAGER:SYSTEM_BACKUP $! $ ON ERROR THEN GOTO FAILURE $ SET PROCESS/PRIVILEGES=ALL $! $ REPLY/ALL - "Full Backup About to Begin. Open Files Will Not Be Saved" $! $ BACKUP /IMAGE DUA2: MUA0:FULL_BACKUP.SAV /REWIND /IGNORE=LABEL_PROCESSING $ DISMOUNT MUA0: $ EXIT $! $FAILURE: $ WRITE SYS$OUTPUT "---> Backup failed" $ WRITE SYS$OUTPUT "" $ DISMOUNT MUA0: $ EXIT

3. Edit the command procedure to reflect:
   • The name of the disk that you want to back up. To back up more than one disk, list each of the devices in the BACKUP command line. For example, you could substitute the following lines for the BACKUP command line in the preceding example:

     . . . $! $ BACKUP/IMAGE WORK_DISK MIA0:WORK_BACK.SAV/REWIND $ BACKUP/IMAGE PAYROLL_DISK MIA0:PAYROLL_BACK.SAV $! . . .

     
     If you plan to perform any incremental backups later, include the /RECORD qualifier in the BACKUP command line.

   • The name of the tape drive that you will use.
   • The name that you want to assign to the save set.
4. Write down the name of the save set that you assigned.
5. Submit the command procedure using the following command line (if you gave your procedure a file name other than SYS$MANAGER:SYSTEM_BACKUP.COM, substitute the appropriate file name):

   SUBMIT/NOPRINT/AFTER="TOMORROW+2:0"/QUEUE=queue_name SYS$MANAGER:SYSTEM_BACKUP

6. Be sure to change the tape daily and make sure that a tape is physically loaded on the device that you specified. When the backup is complete, keep the backup tape in a safe place and do not use the tape again until after you make another image backup of your disks.

To stop the procedure after you have submitted it, use the DELETE/ENTRY command. To find the entry number, use the SHOW ENTRY command. For example:

$ SHOW ENTRY Entry Jobname Username Blocks Status ----- ------- -------- ------ ------ 14 SYS_BACKUP TPROULX Holding until 19-APR-2000 02:00 On generic batch queue CLUSTER_BATCH $ DELETE/entry=583

11.15.7.2 Using a Command Procedure for Nightly Incremental Backups

You can use a similar command procedure to perform nightly incremental backups of your disks. It might be more convenient to perform nightly incremental backups and weekly image backups if either of the following conditions applies:

• Interactive users are on your system at all times, and system performance is noticeably affected by backups.
• A full backup does not fit on a single magnetic tape, but an incremental backup does. In this case, an image backup requires the presence of an operator (to change the tape), whereas an incremental backup can be run as a batch job.

Suppose that you want to do nightly incremental backups at 11:00 P.M., except on Friday night, when you want to do an image backup. The following command procedure executes an incremental backup on three disks and automatically resubmits itself to run again the following night, except for Friday night.

How to Perform This Task

To use the procedure, follow these steps:

1. From the SYS$MANAGER directory, create the command procedure as shown and call it INCREMENTAL_BACKUP.COM.

   $! $! Resubmit this procedure -- $ SUBMIT/AFTER="TOMORROW+23:0" SYS$MANAGER:INCREMENTAL_BACKUP $! $ TODAY = f$cvtime("today",,"weekday") $ IF TODAY .EQS. "Friday" THEN GOTO DONE $! $ ON ERROR THEN GOTO FAILURE $ SET PROC/PRIV=(OPER,BYPASS) $! $ REPLY/ALL - "Incremental Backup About to Begin. Open Files Will Not Be Saved" $! $ BACKUP/RECORD/SINCE=BACKUP DRA0:[000000...] - MIA0:INCREMENT1.SAV /LABEL=INC1 $ BACKUP/RECORD/SINCE=BACKUP DRA1:[000000...] - MIA1:INCREMENT2.SAV /LABEL=INC2 $ BACKUP/RECORD/SINCE=BACKUP DRA2:[000000...] - MIA2:INCREMENT3.SAV /LABEL=INC3 $ DISMOUNT MIA0: $ DISMOUNT MIA1: $ DISMOUNT MIA2: $ EXIT $! $FAILURE: $ WRITE SYS$OUTPUT "---> Backup failed" $ WRITE SYS$OUTPUT "" $ DISMOUNT MIA0: $ DISMOUNT MIA1: $ DISMOUNT MIA2: $ EXIT

2. Edit the procedure to reflect:
   • The names of the disks that you want to back up
   • The name of the tape drive that you will use
   • The volume label of the tape
   • The name that you want to assign to the save set
   • The day of the week (if any) to be omitted in the incremental backup
   
   In this example, the incremental backup will not be performed on Friday, reserving that day for an image (full) backup.
3. Be sure that an image backup has been made and also be sure that you continue to make regular image backups. When you make your image backups, be sure to use the /RECORD qualifier (as well as the /IMAGE qualifier) in your BACKUP command line.
4. Submit the command procedure using the following command line (if you gave your procedure a file name other than SYS$MANAGER:INCREMENTAL_BACKUP.COM, substitute the appropriate file name):

   $ SUBMIT/AFTER=23 SYS$MANAGER:INCREMENTAL_BACKUP

5. Be sure that a tape is physically loaded on the device that you specified. When the incremental backup is complete, keep the tape in a safe place and do not use the tape again until you make another image backup.

You can use the following command procedure to interactively back up a disk to a magnetic tape.

How to Perform This Task

To use the procedure, perform the following steps:

1. Create the command procedure in your directory:

   $ ! Command procedure DAILYBACK.COM $ ! $ ! Execute this command procedure interactively $ ! by entering the command @[directory]DAILYBACK $ ! at the DCL prompt. $ ! $ ! The BACKUP command in this procedure contains the $ ! output save-set qualifier /REWIND. Therefore, this $ ! command procedure always initializes the output tape. $ ! $ ON ERROR THEN GOTO FAILURE $ INQUIRE DRIVE "Enter the drive name (without a colon)" $ ALLOCATE 'DRIVE' $ INQUIRE SAVESET_SPEC "Enter the save-set specifier" $ INQUIRE LBL "Enter the tape label" $ INQUIRE EXP "Enter the tape expiration date" $ BACKUP/NOASSIST/RECORD/IGNORE=INTERLOCK/SINCE=BACKUP - [...] 'DRIVE':'SAVESET_SPEC'/REWIND/LABEL='LBL'/TAPE_EXPIRATION='EXP' $ DISMOUNT 'DRIVE' $ EXIT $! $FAILURE: $ WRITE SYS$OUTPUT "---> Backup failed" $ WRITE SYS$OUTPUT "" $ DISMOUNT 'DRIVE' $ EXIT

2. Run the procedure and enter the drive, save set, tape label, and tape expiration information.
3. After the specified tape drive is allocated, BACKUP searches the tape's volume header record for a volume label and compares the label you specified with the /LABEL qualifier. If the volume header record contains no volume label, BACKUP writes the label and expiration date you specified to the volume header record and initializes the tape. Otherwise, BACKUP compares the tape's volume label with the label you specified and ensures that the tape is expired.
   If the tape is not expired or the label does not match, the command procedure exits. If the tape is expired and the label matches, BACKUP writes the expiration date you specified to the volume header record and initializes the tape. After initializing the tape, BACKUP saves all files in the current default directory tree that have been created or modified since the last save operation to a save set with the name you specified.

Volume shadowing maintains multiple copies of the same data on two or more disk volumes. If you use volume shadowing on your system, you can form a shadow set by uniting individual disk volumes (shadow set members). Volume shadowing duplicates data on each member of the shadow set. Per-disk licensing is available for each disk you will be including in a shadow set. This option is effective in a cluster where you intend to shadow only a small number of disks. However, if you have larger systems with many more disks to shadow, traditional capacity (per-CPU) licenses may be more appropriate.

Limits on the numbers of disks allowed in shadow sets are shown in Table 11-7.

Table 11-7 Number of Shadow Sets Supported

Type of Shadow Set	Sets Supported
Single member	Unlimited sets
Multimember	Total of 400 disks in two- and three-member sets, or both

These limits apply per cluster. For example, 400 total disks could be configured into 200 two-member shadow sets or into 133 three-member shadow sets per cluster. If single, two-member, and three-member shadow sets are all present on a single cluster, then a maximum of 400 disks may be contained in the two- and three-member shadow sets.

You can use the firmware implementation of RAID level 1 (shadowing) to create shadow sets using the SCSI (Small Computer Systems Interface) disks attached locally to a single SWXCR-xx controller. The StorageWorks RAID Array 210 Subsystem (SWXCR-EA or SWXCR-EB EISA Backplane RAID controllers) and the StorageWorks PCI Backplane RAID controller (SWXCR-PA or SWXCR-PB) have their own firmware implementations of RAID, levels 0, 1, and 5.

SCSI disks connected to these controllers can also be included in shadow sets created using host-based volume shadowing for OpenVMS. For example, with host-based volume shadowing, you can create a RAID1 shadow set containing two like disks, each of which is attached to a separate SWXCR-xx RAID controller located within a cluster. SCSI disks can be configured as shadow sets when attached to systems running volume shadowing for OpenVMS.

For directly connected SCSI devices that have been powered down or do not answer to polling, the elapsed time before a device is removed from a shadow set approaches one minute. In all other situations, the elapsed time closely approximates the number of seconds specified in the SHADOW_MBR_TMO parameter.

Volume shadowing checks for geometries and maximum logical block numbers (LBNs) on devices. This enables devices such as the RZ28 and the RZ28B to operate in the same shadow set. Even though their device IDs differ, their geometries and maximum LBNs will match when configured on like controllers (two HSJ controllers, for example).

When you create a shadow set, individual users access it as a virtual unit. For example, you could create a virtual unit DSA1 that consists of the disks named DUA1:, DUA2:, and DUA3. Users cannot access the individual shadow set members directly, but can perform operations on the virtual unit (DSA1:).

Because of the way volume shadowing duplicates data on each disk in the shadow set, there are special considerations for backing up a shadow set. One strategy for backing up shadow sets involves using the OpenVMS Backup utility.

How to Perform This Task

The proper procedure for using BACKUP to back up a shadow set is described in detail in the Volume Shadowing for OpenVMS manual, and can be summarized as follows.

1. Make sure that all shadow set members are full members; none of the members should be in a merge or copy state.
2. Dismount the entire shadow set.
3. Re-create the shadow set less one member. The data on the excluded member will mirror the data on the shadow set members.
4. Mount the former shadow set member for the backup.
5. Perform an image backup on the former shadow set member.
6. Dismount the former shadow set member when the backup is complete.
7. Add the shadow set member that you backed up.

To mount a disk in the StorageWorks RAID Array 110 Subsystem in a host-based shadow set, you must use the /OVERRIDE=NO_FORCED_ERROR qualifier with the MOUNT command.

The StorageWorks RAID Array 110 Subsystem does not support the READ/WRITE LONG SCSI commands that are necessary for implementing the FORCED ERROR function in SCSI. Without FORCED ERROR, you must override that check by the shadowing driver.

11.15.8.2 Assisted Merging in Mixed-Architecture Clusters

Assisted merging, also known as minimerge, is disabled if shadow sets are mounted on an OpenVMS Alpha node and also on other types of nodes in the same cluster. To reenable assisted merging, apply the CSCPAT (TIMA) kit to all OpenVMS Cluster nodes mounting the shadow set.

With minimerge disabled, shadowing will continue to function normally. However, a full merge will always be done when a merge operation is required. A full merge takes considerably longer to complete than a minimerge operation; Compaq recommends that you install the CSCPAT (TIMA) kit.

11.16 Restoring User Disks

Occasionally you may want to restore the backup copy of an entire disk. For example, if the disk drive fails, you could restore the backup copy to a working disk. By occasionally saving and restoring an image backup, you can also prevent disk fragmentation.

The way in which you restore a disk depends on whether the most recent backup was an image (full) or incremental backup. Section 11.16.1 describes the process for restoring a disk when the most recent backup was an image backup. Section 11.16.2 describes the process for restoring a disk when one or more incremental backups were performed since the most recent image backup.

11.16.1 Restoring Image Backups

This section describes how to restore the entire contents of a disk when your most recent backup was an image backup (using the /IMAGE qualifier, as described in Section 11.15.2).

How to Perform This Task

To restore an image backup, use the following procedure.

1. Mount the disk to which you will restore the files, using the MOUNT/FOREIGN command as described in Section 11.8.2.
2. Load and mount the volume. If the backup is contained in a Files--11 save set, make sure you mount the volume in the Files--11 format. If the backup is contained in a sequential disk save set, make sure you load the volume and mount it using the MOUNT/FOREIGN command. If the backup copy is on a tape save set, load the first tape.
3. If you do not know the name of the save set, perform one of the following actions:
   • If the save set is on a disk, make sure the disk is mounted in the Files--11 format and use the DIRECTORY command to determine the name of the save set. For example:

     $ DIRECTORY BACKUP_DISK:[BACKUPS] Directory SYS$SYSDEVICE:[BACKUPS] 19APRIL2000.SAV;1 Total of 1 file.

     
     The save set is named 19APRIL2000.SAV.

   • If the save set is on magnetic tape, load the tape and then enter the following command, substituting the name of your tape drive for MIA1:

     $ BACKUP/LIST/REWIND MIA1: Listing of save set(s) Save set: 19APRIL2000.SAV Written by: SYSTEM UIC: [000001,000004] Date: 19-APR-2000 22:03:03.63 . . .

     
     The save set is named 19APRIL2000.SAV.

4. To restore the save set, enter the BACKUP command with the /IMAGE qualifier, using the following syntax:

   BACKUP/IMAGE device:save-set-specifier [/SAVE_SET] output-device

   
   If your backup save set is on a disk or diskette, then you must also use the /SAVE_SET qualifier immediately after the save-set specifier (device:save-set-specifier).

5. If your backup save set is on more than one tape, disk, or diskette, BACKUP dismounts and unloads the current volume. Load the next volume when BACKUP prompts for it.
6. Use the /NOUNLOAD qualifier to dismount the disk onto which you just restored the files.

Example

The next example shows how to restore an image backup, using the following assumptions:

• The saved files are contained in a tape save set named FULL_BACKUP.SAV. This save set is the result of an image backup.
• The tape containing the saved copy of the disk contents is loaded on MIA1.
• DUA2: is the device name of the disk to which the files will be restored.

$ MOUNT/FOREIGN DUA2:(1) %MOUNT-I-MOUNTED, DISK1 mounted on _DUA2: $ BACKUP/IMAGE MIA1:FULL_BACKUP.SAV/REWIND DUA2:(2) $ DISMOUNT/NOUNLOAD DUA2:(3)

In this example, the individual command lines perform the following actions:

	privacy and legal statement
6017PRO_050.HTML