Updated: 11 December 1998

OpenVMS System Manager's Manual

When backing up your system disk, you must understand the functions of the /IMAGE and /PHYSICAL qualifiers to the BACKUP command before using standalone BACKUP:

Qualifier	Function
/IMAGE	Lets you create a functionally equivalent copy of the entire system disk. When restored, files from an image backup are placed contiguously on the system disk, eliminating disk fragmentation.
/PHYSICAL	Copies, saves, restores, or compares the entire system disk in terms of logical blocks, ignoring any file structure.

For a complete description of the Backup utility qualifiers, refer to the OpenVMS System Management Utilities Reference Manual.

How to Perform This Task

To perform an image backup of the system disk to tape, use the following procedure:

1. Obtain blank tape cartridges or magnetic tapes that you can use for the backup operation.
2. Write-enable the tape. To write-enable a tape cartridge, slide the write-protect switch away from the tape cartridge label. To write-enable a tape, insert a write-enable ring in the back of the tape reel.
3. Insert a tape into the tape drive.
4. Determine the device name of the system disk you are backing up. (See Section 7.2 for information about determining the names of your devices.) To display the device name of the system disk you are booted from, enter the DCL command SHOW LOGICAL SYS$SYSDEVICE.
5. Depending on your configuration, either boot standalone BACKUP or start the menu system:
   • If you have access to the OpenVMS Alpha or VAX operating system distribution compact disc, start the menu sytem described in Section 10.17.1.
   • If you do not have access to the OpenVMS VAX operating system distribution compact disc, boot standalone BACKUP as described in either Section 10.17.2.2 or Section 10.17.2.4.
6. Enter the BACKUP command in the following format:

   BACKUP/IMAGE/VERIFY input-specifier: output-specifier:saveset.BCK/REWIND/LABEL=label

   
   where:

   • input-specifier is the device name of the system disk.
   • output-specifier is the device name of the drive that you want to hold the backup copy.
   • saveset.BCK is the name of the save set. The name should reflect the contents of the tape (for example, OCT_31_1998.BCK) and cannot exceed 17 characters in length.
   • label is the volume label of the tape in the drive. If the tape has been initialized already, use the same volume label that was assigned by the INITIALIZE command.
   
   For example:

   $ BACKUP/IMAGE/VERIFY DUA1: MUA0:DEC_31_BACKUP.BCK/REWIND/LABEL=WKY101

7. The following message indicates that BACKUP has transferred the files and is verifying the accuracy of the backup copy:

   %BACKUP-I-STARTVERIFY, starting verification pass

8. If your system disk contains more data than a single tape cartridge or magnetic tape can store, the procedure displays the following messages and prompt:

   %BACKUP-I-RESUME, Resuming operation on volume 2 %BACKUP-I-READYWRITE, Mount volume 2 on _MUA0: for writing Enter "YES" when ready.

   
   If you do not receive these messages, see step 9. If you do receive these messages, perform the following steps:

   1. Remove the backup tape from the drive.
   2. Label it COMPLETE SYSTEM BACKUP and include the date and the number of the tape in the sequence.
   3. Write-protect the backup tape.
   4. Write-enable another scratch tape and insert it into the drive.
   5. When you are ready to continue, enter Y (for YES) and press Return.
   6. The procedure displays the following message, which indicates that it has transferred the files and is verifying the accuracy of the backup copy:

      %BACKUP-I-STARTVERIFY, starting verification pass

      
      Each time the procedure displays a mount request, follow steps a through e.

9. If you are using standalone BACKUP, when the backup is finished, the system displays the following message:

   %BACKUP-I-PROCDONE, Operation completed. Processing finished at 19-MAY-1998 15:30. If you do not want to perform another standalone BACKUP operation, use the console to halt the system. If you do want to perform another standalone BACKUP operation, ensure the standalone application volume is online and ready. Enter "YES" to continue:

   
   Continue with step 11.

10. If you are using the menu system, the DCL prompt appears after the backup is finished. Log out and choose the Shutdown option from the menu.
11. Remove the backup tape from the drive. Label it COMPLETE SYSTEM BACKUP, number it (if you used more than one cartridge), and include the date.
12. Write-protect the tape cartridge or magnetic tape.
13. Halt the system.
14. Reboot the system.
15. Store the backup tapes in a safe place.

If a problem occurs that renders your system disk unbootable, you can restore the system disk from your backup copy.

How to Perform This Task

To restore the system disk from tape, use the following procedure.

1. Depending on your configuration, either boot standalone BACKUP or start the menu system:
   • If you have access to the OpenVMS Alpha or VAX operating system distribution compact disc, start the menu system described in Section 10.17.1.
   • If you do not have access to the OpenVMS VAX Version operating system distribution compact disc, boot standalone BACKUP as described in either Section 10.17.2.2 or Section 10.17.2.4.
2. Determine the device name of the system disk you want to restore. (See Section 7.2 for information about determining the names of your devices.)
3. Insert the first tape of the complete system disk backup into the drive. Make sure the tape is write-protected.
4. Enter the BACKUP command in the following format:

   BACKUP/IMAGE/VERIFY input-specifier:saveset.BCK/REWIND output-specifier:

   
   where:

   • input-specifier is the device name of the drive that holds the backup copy.
   • saveset.BCK is the name of the save set.
   • output-specifier is the device name of the system disk that you are restoring.
   
   For example:

   $ BACKUP/IMAGE/VERIFY MUA0:DEC_31_BACKUP.BCK/REWIND DUA0:

5. The procedure displays the following message:

   %BACKUP-I-STARTVERIFY, starting verification pass

6. If your system disk contained more data than one tape could store, you receive the following messages and prompt:

   %BACKUP-I-RESUME, Resuming operation on volume 2 %BACKUP-I-READYREAD, Mount volume 2 on MUA0: for reading Enter "YES" when ready.

   
   If you do not receive these messages, see step 7. If you do receive these messages, perform the following steps:

   1. Remove the backup tape from the drive.
   2. Insert the next backup tape into the drive.
   3. When you are ready to continue, enter Y (for YES) and press Return.
   4. The procedure displays the following message:

      %BACKUP-I-STARTVERIFY, starting verification pass

      
      Each time the procedure displays a mount request, follow steps a through c.

7. If you are using standalone BACKUP, when the restore is finished the system displays the following message:

   %BACKUP-I-PROCDONE, Operation completed. Processing finished at 19-MAY-1998 15:30. If you do not want to perform another standalone BACKUP operation, use the console to halt the system. If you do want to perform another standalone BACKUP operation, ensure the standalone application volume is online and ready. Enter "YES" to continue:

   
   Continue with step 9.

8. If you are using the menu system, the DCL prompt appears after the restore is finished. Log out and choose the shutdown option from the menu.
9. Remove the last backup tape from the drive.
10. Halt the system.
11. Reboot the system.
12. Store the backup tapes in a safe place.

To eliminate disk fragmentation, perform a disk-to-disk image backup without using the /SAVE_SET qualifier. This creates a functionally equivalent copy of the entire system disk, on which files are stored contiguously.

How to Perform This Task

To perform a disk-to-disk image backup, use the following procedure:

1. Obtain a disk with enough storage capacity to use for the backup. Make sure the disk does not contain files you need, because standalone BACKUP initializes the output disk.
2. Determine the device name of the system disk you are backing up. (See Section 7.2 for information about determining the names of your devices.) To display the device name of the system disk you are booted from, enter the DCL command SHOW LOGICAL SYS$SYSDEVICE.
3. Depending on your configuration, either boot standalone BACKUP or start the menu system:
   • If you have access to the OpenVMS Alpha or VAX operating system distribution compact disc, start the menu system described in Section 10.17.1.
   • If you do not have access to the OpenVMS VAX operating system distribution compact disc, boot standalone BACKUP as described in either Section 10.17.2.2 or Section 10.17.2.4.
4. Enter the BACKUP command in the following format:

   BACKUP/IMAGE/VERIFY input-specifier: output-specifier:

   
   where:

   • input-specifier is the device name of the system disk.
   • output-specifier is the device name of the drive that you want to hold the backup copy.
   
   For example:

   $ BACKUP/IMAGE/VERIFY DUA0: DUA1:

5. BACKUP displays the following message, which indicates that it has transferred the files and is verifying the accuracy of the backup copy:

   %BACKUP-I-STARTVERIFY, starting verification pass

6. If you are using standalone BACKUP, when the backup is finished the system displays the following message:

   %BACKUP-I-PROCDONE, Operation completed. Processing finished at 19-MAY-1998 15:30. If you do not want to perform another standalone BACKUP operation, use the console to halt the system. If you do want to perform another standalone BACKUP operation, ensure the standalone application volume is online and ready. Enter "YES" to continue:

   
   Continue with step 8.

7. If you are using the menu system, the DCL prompt appears after the backup is finished. Log out and choose the shutdown option from the menu.
8. You can use the backup output disk as the system disk. Files are stored contiguously on the output disk, eliminating disk fragmentation.
9. Store the original system disk.
10. Halt the system.
11. Reboot the system using the newly created system disk.

On VAX systems, you can back up the system disk to an InfoServer tape and restore the system disk from an InfoServer tape.

How to Perform This Task

1. Boot the system from the SYS1 directory using the current version of the OpenVMS CD-ROM, which can be in a reader on the InfoServer or on a local drive.

   Note The boot command you use for your computer depends on the type of system you have. For more information about booting your system, refer to the installation and operations supplement for your computer.

2. Choose option 1 from the menu system.
3. At the prompt, you can perform the backup of your system disks.

Example 10-1 shows the procedure for backing up a system disk to an InfoServer tape.

Example 10-1 System Disk Backup to an InfoServer Tape

>>> B/R5:10000100 ESA0 Bootfile: ISL_SVAX_071 -ESA0 Network Initial System Load Function Version 1.1 FUNCTION FUNCTION ID 1 - Display Menu 2 - Help 3 - Choose Service 4 - Select Options 5 - Stop Enter a function ID value: 3 OPTION OPTION ID 1 - Find Services 2 - Enter known Service Name Enter an Option ID value: 2 Enter a Known Service Name: VMS062 OpenVMS VAX Version 7.2 Major version id = 2 Minor version id = 0 %SYSINIT-E, error opening page file, status = 0000025C %SYSINIT-E, error opening swap file, status = 0000025C %SYSINIT, primary PAGEFILE.SYS not found; system initialization continuing %SYSINIT, no dump file - error log buffers not saved %SYSINIT-E, error mounting system device, status = 00000F64 $! Copyright (c) 1998 Compaq Computer Corporation. All rights reserved. $set noverify Copyright © (c) 1998 Compaq Computer Corporation. All rights reserved. Installing required known files... Configuring devices... **************************************************************** The menu can be used to execute DCL commands and procedures for various "standalone" tasks, such as backing up the system disk. Please choose one of the following: 1) Execute DCL commands and procedures 2) Shut down this system Enter CHOICE or "?" to repeat menu: (1/2/?) 1 WARNING -- The normal VMS startup procedure has not executed. Some commands and utilities will not work as documented. Enter DCL commands -- Enter "LOGOUT" when done. When you enter "LOGOUT" a logout message will be displayed, and you will be returned to the menu. $$$ MCR ESS$LADCP SHOW SERVICE/TAPE $$$ MCR ESS$LADCP BIND/WRITE/TAPE TZL04_TAPE $$$ MOUNT/FOREIGN MADn $$$ BACKUP/IMAGE DKA100: MADn:SYS_DISK.BCK/SAVE_SET . . . $$$ LOGOUT Process SYSTEM_1 logged out at 2-FEB-1998 23:35:17.52 **************************************************************** The menu can be used to execute DCL commands and procedures for various "standalone" tasks, such as backing up the system disk. Please choose one of the following: 1) Execute DCL commands and procedures 2) Shut down this system Enter CHOICE or "?" to repeat menu: (1/2/?)

10.18 Ensuring Data Integrity

BACKUP has several qualifiers for further ensuring the integrity of your backups. Compaq recommends using these qualifiers if you want to achieve maximum data integrity. This section describes some of the ways you can increase data integrity with BACKUP. For more information about these qualifiers, refer to the OpenVMS System Management Utilities Reference Manual.

10.18.1 /CRC Qualifier

The /CRC qualifier enables the software cyclic redundancy check (CRC). The default is /CRC; you must specify /NOCRC to disable checking. Disabling checking reduces processing time, but increases the risk of data error.

As an output save-set qualifier, /CRC writes the CRC checking code into the blocks of the output save set.

As an input save-set qualifier, /CRC checks the CRC information in the input save set.

Compaq recommends that you use the CRC. Although it increases processing time, it also improves data integrity.

10.18.2 /GROUP_SIZE Qualifier

This output save-set qualifier causes BACKUP to write redundant data to the output save set. This allows BACKUP to attempt to correct read errors during the backup restore operation. Use the /GROUP_SIZE qualifier to define the number of blocks in each group of redundant information. For example:

$ BACKUP/IMAGE/RECORD _From: DKA100: _To: MKB100:BACKUP.SAV/LABEL=WKY101/GROUP_SIZE=20

This command adds a recovery block after every 20 blocks of saved data. This allows BACKUP to recover a corrupted data block for every 20 blocks of saved data. The value of the /GROUP_SIZE qualifier defaults to 10.

Although using this qualifier increases the size of the save set and the processing time for the operation, Compaq recommends using the /GROUP_SIZE qualifier to increase data integrity.

10.18.3 /IGNORE Qualifier

Compaq recommends that you back up your system when no interactive users are logged in. This is because if BACKUP encounters an open file during a save operation, it issues an error message and does not copy the file.

You can instruct the backup procedure to save open files by using the /IGNORE=INTERLOCK qualifier on the BACKUP command. When you use the /IGNORE=INTERLOCK qualifier, the contents of the file at the moment of the backup are saved.

The /IGNORE=INTERLOCK qualifier is useful for files that are constantly open (and would therefore not otherwise be saved). However, you must recognize that you might be saving inconsistent data, depending on the applications that are writing to the open files (for example, open application transactions or file data cached in memory). Also, because of the way BACKUP scans directories, any activity in a directory (such as creating or deleting files) can cause files to be excluded from the backup. In general, it is best to back up your system when a minimum number of files are open.

Also, because of the way the file system works, using the /IGNORE=INTERLOCK qualifier to back up open files affects subsequent incremental backups. For example, you can back up an open file with the BACKUP/IMAGE/RECORD/IGNORE=INTERLOCK command. However, the backup date field of the file is not updated until you close the file. If the file remains open during subsequent incremental backups, it is not included in those backups because its backup date field is not as recent as the last image backup.

10.18.4 /LOG Qualifier

Use the /LOG qualifier to the BACKUP command to display the file specification of the files that BACKUP processes during a backup operation. For example, if you are copying files in a directory, you can use the /LOG qualifier to display the file specification of each file copied:

$ BACKUP/LOG _From: WORK3:[OCONNELL]*.* _To: WORK1:[OCONNELL.SCRATCH]*.* %BACKUP-S-CREDIR, created WORK1:[OCONNELL.SCRATCH.COM] %BACKUP-S-CREATED, created WORK1:[OCONNELL.SCRATCH]DECW$MAIL.DAT;2 %BACKUP-S-CREATED, created WORK1:[OCONNELL.SCRATCH]DECW$SM.LOG;42 %BACKUP-S-CREATED, created WORK1:[OCONNELL.SCRATCH]DECW$SM.LOG;41 . . .

10.18.5 /VERIFY Qualifier

Use the /VERIFY qualifier to cause BACKUP to compare the contents of the input and output specifiers after a save, restore, or copy operation. When BACKUP is executing the verification pass, it displays the following message:

%BACKUP-I-STARTVERIFY, starting verification pass

If BACKUP finds differences between the input and output files, it issues an error message.

Compaq recommends that you use the /VERIFY qualifier. Although it increases processing time, it also improves data integrity.

Backing Up a Save Set Twice Using /VERIFY Qualifier

The problem described in this section applies to TZ87 and TZ88 tape drives and to TZ89 tape drives. If you mount a tape /FOREIGN and then back up files to a save set twice, the second save set reports errors under the following conditions:

• The two save sets have the same name.
• You use the /VERIFY qualifier with the BACKUP command.
• The second BACKUP command has a /BLOCKSIZE of less than 4096 bytes (8*512).
• The save set is not sufficiently large, for example:

  For BACKUP /BLOCKSIZE=	The Files Must Total at Least
  4000	6300 1 blocks
  3580	5400 1 blocks

  ---

  ¹Rounded to nearest hundred
  

  ---

Error messages similar to the following ones are displayed:

%BACKUP-I-STARTVERIFY, starting verification pass %BACKUP-E-READERR, error reading MKB300:[]SET.SAV; -SYSTEM-W-DATAOVERUN, data overrun %BACKUP-E-INVBLKSIZE, invalid block size in save set %BACKUP-E-INVRECSIZ, invalid record size in save set %BACKUP-F-READERRS, excessive error rate reading MKB300:[]SET.SAV; -SYSTEM-W-DATAOVERUN, data overrun

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