HP OpenVMS System Manager's Manual, Volume 1:...

Using BACKUP

Setting Process Quotas for Efficient Backups

Understanding OPCOM and Volumes

Using Disks and Tapes  

1. Determine the device name.
2. Allocate the device.
3. Initialize the volume (optional).
4. Mount the device (for disks only; BACKUP mounts tapes automatically).

These tasks are described in Managing Storage Media. This chapter describes specifically how these tasks relate to BACKUP. Note that all disk operations in this chapter also apply to diskettes.

Understanding Volume Initialization  

Initializing a volume completes the following actions:

• Formats it in the OpenVMS Files-11 format



• Assigns it an ANSI label



• Removes links to any existing files (effectively erasing them)



• Writes a tape expiration date and volume protection data to the volume header record of the tape

Initializing a volume removes links to existing files on the volume, effectively erasing the files. Do not initialize a volume that contains data you want to keep.

When to Initialize Volumes  

You must initialize a volume for use with BACKUP if any of the following conditions exist:

• The volume is new and has not been formatted in the Files-11 format.



• You want to remove access to data stored on the volume.



• You want to change the volume label, expiration date, or volume protection data.



• The volume contains a non-ANSI or non-ISO label.

Methods of Volume Initialization show the three ways to initialize a volume.

Table 6   Methods of Volume Initialization

Method	For More Information
Before a backup operation with the DCL command INITIALIZE	Initializing Volumes
On the BACKUP command line with the /REWIND qualifier (for tapes only)	Tapes
On the BACKUP command line with the /INITIALIZE qualifier (for disks only)	Initializing Disks

Tapes  

Instead of using the INITIALIZE command and then performing a backup operation, you can initialize a tape and perform a backup operation by entering one BACKUP command.

How to Perform This Task

To initialize a tape volume on the BACKUP command line, add the /REWIND and /LABEL qualifiers to the output specifier. The /REWIND qualifier rewinds and initializes the volume. The /LABEL qualifier allows you to specify the volume label.

Magnetic tape volume labels can contain a maximum of six characters. You can use any ANSI "a" character in a magnetic tape volume label. The ANSI "a" characters include numbers, uppercase letters, and any of the following nonalphanumeric characters: ! " % ' ( ) * + , _ . / : ; < = > ?

If you use any nonalphanumeric characters, you must enclose the volume label with quotation marks.

Label your magnetic tapes according to the data contained on the tapes. The following table presents some suggestions for labeling tapes:

Label	Type of Backup	Expiration Date
DLY101	Daily, group 1, volume number 1	Expires in 7 days
DLY102	Daily, group 1, volume number 2	Expires in 7 days
WKY101	Weekly, group 1, volume number 1	Expires in 4 weeks
WKY201	Weekly, group 2, volume number 1	Expires in 4 weeks
MTH101	Monthly, group 1, volume number 1	Expires in 12 months
YRY101	Yearly, group 1, volume number 1	Expires in 5 years

Note that:

• If the tape volume has already been initialized with a label that is different from the label you specify on the BACKUP command line, BACKUP displays an error message about the label mismatch. For more information, see Understanding BACKUP Tape Label Processing.



• If the tape is not expired, BACKUP displays the following error message:

  %INIT-F-FILNOTEXP, file is not expired

  If you have either VOLPRO privilege or write access to the volume, or you are the owner of the volume, you can use the DCL command INITIALIZE/OVERRIDE=EXPIRATION to initialize the magnetic tape.
  
  You can also reenter the BACKUP command line using the /IGNORE=LABEL_PROCESSING qualifier (refer to the HP OpenVMS System Management Utilities Reference Manual).



• If the volume was previously initialized with the output save-set qualifiers /REWIND and /PROTECTION, you must either own the volume (your UIC matches the owner UIC of the volume) or have VOLPRO privilege.

Example

$ BACKUP [ACCOUNTS.JUNE] MUA0:JUNE.BCK/REWIND/LABEL=MTH101

Initializing Disks  

Instead of using the INITIALIZE command and then performing a backup operation, you can initialize a disk and perform a backup operation by entering one BACKUP command.

How to Perform This Task

The two ways to initialize a disk during a backup operation are:

• When you perform an image copy to disk, BACKUP automatically initializes the output disk, effectively erasing any existing files and volume-initialization data on the disk. To preserve volume-initialization data on the output disk, use the /NOINITIALIZE qualifier.



• When you create a sequential disk save set, BACKUP does not initialize the output volume (by default). You can, however, instruct BACKUP to initialize the output volume using the /INITIALIZE qualifier.

Examples

1. The following command shows how to initialize a disk on the BACKUP command line:

   $ BACKUP/IMAGE DUA1: DUA2:

   This command initializes DUA2: using the volume-initialization data from DUA1. BACKUP then copies the contents of DUA1: to DUA2:, effectively erasing any existing files on DUA2. Note that the files on DUA2: are stored contiguously, eliminating disk fragmentation.
2. The following command shows how to preserve volume-initialization data on the output disk during an image copy:

   $ BACKUP/IMAGE DUA1: DUA2:/NOINITIALIZE

   This command causes BACKUP to initialize DUA2:, preserving the initialization data on that volume. BACKUP then copies the contents of DUA1: to DUA2:, effectively erasing any existing files on DUA2.
3. These commands cause BACKUP to initialize DJA2:, effectively erasing any existing files:

   $ MOUNT/FOREIGN DJA2:
   %MOUNT-I-MOUNTED, USER1 mounted on _DJA2:
   $ BACKUP/IMAGE DUA1: DJA2:DAILY.SAV/INITIALIZE

   BACKUP then creates an image backup of DUA1: in the sequential disk save set DUA2:[000000]DAILY.SAV. If the save set exceeds the available disk space, BACKUP prompts for another volume. BACKUP initializes the new volume and extends the save set in the master file directory ([000000]) of the new volume. (For more information about save sets, see Understanding Save Sets. For more information about the /INITIALIZE qualifier, refer to the HP OpenVMS System Management Utilities Reference Manual.)

Mounting a Volume  

Mounting a volume makes it available to the system. BACKUP automatically mounts tapes when you use them for a backup operation. Most disks on your system are mounted at system startup. This section describes how to explicitly mount volumes.

If you are planning to write a save set to a disk, decide whether the save set will be written in standard Files-11 format or in sequential-disk format:

• If the save set will be written in standard Files-11 format, the target disk must be mounted as a Files-11 disk.



• If a save set will be written in sequential-disk format (for example, if the save set occupies more than one disk), the target disk must be mounted as a foreign device by specifying the command qualifier /FOREIGN to the DCL command MOUNT.

How to Perform This Task

1. Enter the SHOW DEVICES command in the following format to check whether the device is already mounted:SHOW DEVICES device-name
2. Enter the MOUNT command in the following format:MOUNT [/FOREIGN] device-name [volume-label] [logical-name]where:

   device-name	is the name of the drive that holds the volume you want to mount.
   volume-label	is the alphanumeric identification you assigned to the volume with the INITIALIZE command. For disk volumes, labels can have a maximum of 12 characters; for magnetic tape volumes, labels can have a maximum of 6 characters. You do not need to add this parameter if you are mounting the volume with the /FOREIGN qualifier.
   logical-name	is an optional 1- to 255-character alphanumeric specification that you want to associate with the volume.

   
   

Example

$ SHOW DEVICE MU

Device                  Device           Error    Volume         Free    Trans Mnt
 Name                   Status           Count     Label        Blocks   Count Cnt
DAD$MUA6:               Online               0
MOM$MUA6:               Online               0
FRED$MUA6:                Online                 0 

$ MOUNT/FOREIGN FRED$MUA6: TEST DRIVE1

%MOUNT-I-MOUNTED, TEST mounted on _FRED$MUA6:

Dismounting a Volume  

BACKUP does not dismount the last volume of a backup operation (unless you use the /RELEASE_TAPE qualifier). When you finish using a volume, you should dismount it.

How to Perform This Task

Enter the DISMOUNT command in the following format:DISMOUNT device-name

Example

The following command dismounts a tape in drive MUB6:

$ DISMOUNT MUB6:

$ DISMOUNT/NOUNLOAD MUB6:

Setting Process Quotas for Efficient Backups

Understanding OPCOM and Volumes