CHAPTER 9 Managing the Media

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Use the Volumes dialog to perform media management functions. Media management functions include:

From the main dialog, select Backup Volumes from the main dialog to display the Volumes dialog. A sample Volumes dialog is shown in Figure 9 1.

Graphic: Figure 9-1. Sample Volumes Dialog

Changing Volume Label Writing Parameters

Use the Volumes dialog to temporarily change the parameters used when a volume label is written. You can change the blocking factor, block size, and can specify whether bytes are swapped or not.

Blocking

The data on backup volumes is written and read in records. The record size is computed by multiplying the blocking factor by the block size. The default block size is 512 bytes. Increasing the size of these records increases the speed at which a device can read and write volumes, but it is at the expense of system performance.

When backup media pools are created, a default blocking factor and block size are set. Operations involving the volumes in a pool automatically use the default blocking set for that pool.

The blocking used when computing the size of a volume affects how much data the volume stores. In general, the larger the record size, the more data you can fit onto a volume because there are fewer records and, therefore, fewer inter record gaps.

When you add a new volume to a pool or compute the volume's capacity, the default blocking factor for that pool is used. The capacity of a volume is always reported as a multiple of 512 bytes per block.

Changing the Parameters

If the displayed blocking factor, block size and swap bytes setting are appropriate, no action is required.

  1. From the main dialog, select Backup Volumes from the main dialog to display the Volumes dialog (Figure 9 1).

  2. Select a pool from the Pool list box. Any devices and volumes associated with the selected pool are displayed in the Device list box and the Volumes list box (Figure 9 1).

  3. From the Volumes list box, select the volume for which you want to change blocking information.

  4. Complete the following fields as described below:

    Caution: If you choose a blocking factor or block size higher than that specified for the selected pool, you may be unable to use this volume for backups unless you also change the size of the blocking factor or block size specified in the pool description.

    Blocking Factor

    Specifies the blocking factor when writing to volumes in the current pool. Output is blocked in either the given number (n) of 512 byte blocks or as specified with the Block Size field. The default blocking factor is 20.

    Block Size

    Specifies the bytes per block used when writing to volumes in the current pool. The block size must be in increments of 512. The default is 512.

    Swap Bytes

    When selected, specifies that bytes are to be swapped when writing to a volume. If you are creating a volume on one host that may be used on another host with a different byte order, you may want to specify that bytes are to be swapped. The default is not selected.

  5. Continue with Adding Volumes to a Pool on page 9 5.

Adding Volumes to a Pool

Note: Before you can add a media volume to a pool, check for an existing media type file by choosing Manage Tables Media Types. If the appropriate media type file does not exist, compute the capacity of a mounted volume, and create a new media types file. See Computing the Capacity of a Mounted Volume on page 9 14 for instructions on computing volume capacity. See Adding a Media Type File on page 6 26 for instructions on creating a media type file.

Adding a tape volume to a media pool creates an electronic label on the tape and adds an entry in the pool's volume table. Use the Volumes option to add volumes to media pools.

Since the message displayed to an operator provides only the name of the tape and the tape drive, it is very useful to name the tapes in one pool on one host differently from those in another pool on another host.

Caution: Make sure there are enough volumes in a media pool to hold a full backup. You CANNOT add volumes during a backup. If there are not enough free volumes, the backup job fails.

Note: You must have operator privileges on the poolmaster from the host you are using to add a volume to a pool on a remote host. For example, the poolmaster is host loki and you are on host thor that has a device associated with the pool. If you do not have either an ALL card or a host thor card with operator privileges, you cannot add volumes to the pool. See page 6 3 for information on assigning privileges.

Displaying Volume Information

  1. From the main dialog, select Backup Volumes from the main dialog to display the Volumes dialog (Figure 9 1).

  2. Select a pool from the Pool list box.

  3. Select a volume from the Volumes list box.

  4. Click the Show button. The Volume Information dialog is displayed (Figure 9 2 ).

Graphic: Figure 9-2. Volume Information Dialog

The current pool and host are displayed at the top of the dialog. The fields in the Volume Information dialog are defined as follows: Volume Name---The name of the volume.
Media Type--- Menu button. Displays the current media type file.
Capacity--- The capacity, in blocks, of the volume.
Location--- The location of the volume.
Blocks Used--- The number of blocks currently in use on the volume. Shown also as a percentage of the total number of blocks. For a new volume, this value is 0.
Usage Count--- The number of times the volume has been written to, including when it was added to the pool. The initial value is "1" and it is incremented when a volume is recycled and reused. The minimum value of this field is the number of dumps on the volume, plus one.
Format--- The current volume format.
Version--- The version level of the BACKUP.UNET software that was running when the volume label was created.
Dumps--- The number of used backup segments on the volume. For a new volume, this value is 0.
Init Date--- The date the volume was added to the pool.

Adding Volumes

Note: Before adding a volume to a media pool, you must choose a device and mount the volume on the device.

  1. Choose Backup Volumes from the main dialog to display the Volumes dialog.

  2. Select a pool from the Pool list box to which the volume will be added (Figure 9 1).

    Graphic: Figure 9-3. Volumes Dialog Showing Pool Selected

  3. Select the device from the Device list box where the volume is mounted.

  4. Click the Add button to display a Volume Information dialog (Figure 9 2 ).

  5. Enter a volume name in the Volume Name field.

  6. Either:
    - Select a media type file by positioning the cursor in the Media Type field and pressing the SELECT mouse button. A pop up menu of the current media types is displayed. The Capacity and Location fields are automatically filled in.
    OR
    - Fill in the Capacity and Location fields.

  7. To save the changes click the Apply button. A volume label is written to the tape and the volume is added to the BACKUP.UNET pool.

Modifying Volume Information

  1. 1. Choose Backup Volumes from the main dialog to display the Volumes dialog.

  2. Select the pool from the Pool list box to which the volume belongs.

  3. Select the volume from the Volumes list box.

  4. Click the Show button. The Volume Information dialog is displayed (Figure 9 2 ).

  5. Change the Volume Name, Media Type, Capacity, and Location as necessary.

  6. To save the changes click the Apply button. The volume information for the specified volume is changed.

Deleting Volumes From a Pool

Note: To reuse a deleted volume, you must first add it to the pool again.

  1. Choose Backup Volumes from the main dialog to display the Volumes dialog.

  2. You must select the pool to which the volume belongs. If you need to change pools, select a pool from the Pool list box.

  3. From the Volumes list box, select the volume or volumes you want to delete.

  4. Click the Delete button.

  5. The system prompts you to confirm the deletion (Figure 9 4).

    Graphic: Figure 9-4. Delete Volume Confirmation Dialog If the volume has blocks currently in use, a warning is displayed that the volume is not free.

  6. To delete the volume, click the OK button. To cancel the deletion click the Cancel button.

Changing the Current Pool

A backup media pool is a collection of volumes, such as 9 track tapes or cartridges, that are managed by a BACKUP.UNET input/output (I/O) provider (IOP). Multiple hosts can be configured to use a single media volume pool, and all volumes in a media pool must be readable by all IOPs associated with that pool.

  1. Choose Backup Volumes from the main dialog to display the Volumes dialog.

  2. The Pool list box displays the pools that are defined with the current host. The current host is displayed in the title of the Volumes dialog, for example Host: usisun, where usisun is the current host name. (If you need to change to another host, return to the BACKUP.UNET main dialog and select another host from the Hosts list box.)

  3. To select another pool, simply point to the pool desired in the Pool list box and select it.

Changing the Current Device

Though each participating system may have a number of devices, each device and each pool can only use one type of media, such as cartridges. You only need to choose a device to perform a function that requires physical access to a volume. These functions include:

You can mount the volume on the device before or after selecting the device.

If more than one device is associated with a pool, the desired device must be selected from those available for the identified pool.

To change the currently selected device:

  1. Choose Backup Volumes from the main dialog to display the Volumes dialog.

  2. The Device list box displays the devices defined to the currently selected pool. The Pool list box displays the pools that are defined with the current host. The current host is displayed in the title of the Volumes dialog, for example Host: usisun, where usisun is the current host name. (If you need to change to another host, return to the BACKUP.UNET main dialog and select another host from the Hosts list box.)

  3. To select another device, simply point to the device desired in the Device list box and select it.

Listing the Volumes in a Pool

Volumes for a specific pool are automatically displayed when you select a pool from the Pool list box.

  1. Choose Backup Volumes from the main dialog to display the Volumes dialog.

  2. Select the pool from the Pool list box for which you want to list the associated volumes. The volumes for that pool are displayed in the Volumes list box.

Identifying a Mounted Volume

To verify the electronic label of a mounted volume, use the Identify button on the Volumes dialog to display the name of the currently mounted volume.

  1. Choose Backup Volumes from the main dialog to display the Volumes dialog.

  2. A pool and corresponding device must be selected before performing this function. The currently selected pool is displayed in the Pool list box. The associated devices are displayed in the Device list box.

  3. If you need to change pools, select another pool from the Pool list box. Then select an associated device in the Device list box. This is the device on which the volume will be mounted.

  4. Mount the volume to be identified on the device you just selected.

  5. Click the Identify button. After a few moments, the name of the mounted volume is displayed.

Computing the Capacity of a Mounted Volume

Use the Compute button in the Volumes dialog to determine the recommended storage capacity (usually 90% of total available capacity) for any type of media supported by BACKUP.UNET. The Compute option computes the recommended storage capacity, in data blocks, of a currently mounted volume by writing binary zeros to the volume.

Caution: The Compute option overwrites any data on the volume. Be sure that the contents of the mounted volume can be erased, or that the volume is empty. BACKUP.UNET refuses to overwrite a BACKUP.UNET volume and returns an error message for this condition.

To compute the capacity of a mounted volume:

  1. Mount an unlabeled volume on the appropriate rewind device. For example, mount a cartridge volume on device /dev/st0.

  2. Choose Backup Volumes from the main dialog to display the Volumes dialog.

  3. A pool and corresponding device must be selected before performing this function. Select a pool from the Pool list box. From the Device list box select the device you mounted the volume on in step 1.

  4. Click the Compute button.

  5. After a while, the computed size is displayed. Write down the size; you will need to create a new media type file.

Scanning a Mounted Volume

Use the Scan button on the Volumes dialog to list the names of all files backed up on the currently mounted backup volume.

  1. Choose Backup Volumes from the main dialog to display the Volumes dialog.

  2. You must select a pool and corresponding device before performing this function. The currently selected pool is displayed in the Pool list box. The associated devices are displayed in the Device list box.

  3. If you need to change pools, select one from the Pool list box. Then select an associated device in the Device list box. This is the device on which the volume will be mounted.

  4. If you would like to see a long listing of the files on the volume, equivalent to a Unix 'ls l', select Long List.

  5. Mount the volume to be scanned on the device you just selected.

  6. Click the Scan button.

  7. After a few moments, the names of the files on the mounted volume are displayed. (See Figure 9 5.)

Graphic: Figure 9-5. Volume Scan Dialog