Backup3G/User Guide/Managing Removable Media

From Documentation

Revision as of 04:35, 19 April 2006

This section provides detailed instructions and worked examples related to media management under backup3G, including:

• setting up the media database
• adding details of a media batch or a single volume
• reading and maintaining media details
• searching online indexes and the media contents table for files and directories.

How To Read and Maintain Media Details

Each volume in the media database is identified by a unique number. You can electronically label tapes and diskettes with this number to prevent them from being accidentally reused by another backup job.

backup3G helps you to track tapes and other media, including:

• used media containing current backup data, in particular media that have been sent offsite or to another onsite location
• unused or expired media that are available to be requested by a backup job or that will become available in the near future

The media database contains two kinds of information: media details (information about media), and media contents (information about the backup data they contain). You can view either media details and contents using the Report and View options in the Media module:

Table 7 — Media contents—viewing and reporting options

See How To Read Backup Media Contents for details of browsing online indexes and information on backup data.

Adding a New Media Location

You must add details of any locations where media are stored:

• onsite and offsite locations used for media storage
• auto-loading devices such as a jukebox or tape silo
• load areas (for example, a computer-room trolley).

When you add drive details, you must specify the location from where media are loaded into the drive.

To add a media location

1. From the backup3G configuration menu, select Maintain tables.
2. Select the ‘Site/Media Location’ table, then select Table > Maintain.
3. Select Maintain > Add.

Enter the following fields:

Location

a short name used to identify the location.

Name

enter the name in full, or a brief description of the location.

Type

the valid types are:

onsite

media will remain here after backups.

offsite

backup media will be held at this site for secure storage.

load_device

an autoloading device such as a tape stacker.

load_area

an interim location used to transport or hold media, such as a trolley or security box.

other

media are neither backed up nor stored here.

Address

the mailing address for returning media to this location.

Phone

used for informational purposes.

Slots

For a load_device, the maximum number of tapes that can be stored.

Press Accept to save this media location.

Adding Backup Media Details

You can add details of a batch of backup media or a single volume. Either way the details stored for each volume are the same. However by storing batch information you can keep track of (for example) the value and reliability of different brands of media over time.

Note You can only add media to an onsite location. 
To use new tapes in an auto-loading device, first add the batch to an onsite location, then allocate the volumes to the load device.

To add a media batch

1. Select Media from the backup3G button bar.
2. Select Maintain > Add batch to display a prompt form which can be filled in as shown in Figure 31.

Figure 31 — Add batch details prompt form

Batch

The batch number.

Media type

Press Choose to display the available media types. If none of these is correct, exit now and add a new media type through Maintain > Media type.

Note A physical media format can have more than one entry in the media table.

Brand

This can be used for media control purposes, for example to keep a purchase history.

Vendor

Used for information/media control only.

Date purchased

Used for information/media control only.

Location

The onsite location where this batch of media will normally be stored (for example, a tape library or load device).

Comments

Reorder details or the vendor’s contact details. Used for information only.

Number in batch

Enter the number of tapes or disks in the batch.

Add to media table?

Select ‘yes’ to add details of each volume to the media table.

If you wish to add the media manually to the media table later, or already have done so, then select ‘no’. Starting media number Enter a media number for the first volume in the batch (only if adding media to media table). Defaults to one more than the current highest.

Press Accept to add this batch of media.

These volumes will be added to the media table with a usage of ‘scratch’, meaning they are now available to be selected for use by a backup job.

If you want to load these new media into a stacker, you must now allocate them to the device’s load location. See Allocating Tapes to a Stacker.

To add details of a single volume

Single volumes can be added directly to the media details table.

1. Select backup3G configuration > Maintain Tables.
2. Select the ‘Media Details’ table, then select Table > Maintain.
3. Select Maintain > Add to display the ‘Add Media Details’ form.
4. Specify the type. The default usage for a new volume is ‘scratch’.
5. Ensure the location is correct and Accept the details.

Figure 32 — Add media details prompt form

To change details of a single volume

This allows you to change details of individual tapes. During day-to-day operations you would typically use this to update fields such as the expiry date of a backup. During initial configuration you can add details of existing media in a library, for example to set the expiry date, usage, date written and location of those volumes in use before backup3G was installed.

1. Select backup3G configuration > Maintain Tables.
2. Select the ‘Media Details’ table from the list of tables.
3. Select the volume you want to update, then select Maintain > Change.

You can maintain any of the following fields:

Number

a unique number to identify this volume.

Type

the media type, which is typically named after its type, length, density, capacity, or label type.

Usage

If this is a new or unused volume, select ‘scratch’. Predefined usage types are:

scratch

currently unused and available for backups and archives.

archive

contains current archive data—not available until expired.

backup

contains current backup data—not available until expired.

release

used for release software—not available for backups.

Written

if Usage is not ‘scratch’, enter the date that the volume was last written. backup3G uses this to balance media usage, by selecting for new backups the volume with the oldest ‘date last written’.

Expires

if this is not a scratch volume, enter the date the backup will expire and the volume will be available for reuse. This will ensure that this volume is not reselected until the expiry date has passed.

Batch

if this volume belongs to a media batch, press Choose to select the batch number. This is optional.

Location

the location where this volume is stored now. This may be an onsite or offsite location, or a load_area or load_device.

Slot

if this is loaded in a load_device, the current slot number.

Date sent offsite

if this volume is currently at another location, enter the date it was sent offsite. Blank if onsite.

Uses

the number of times the volume has been used. You can use this field to decide when to ‘retire’ a volume. A newly labeled volume will have a Uses value of 1.

Description

the backup job description is copied to this field as a description of the contents of the volume.

Set ID

if this volume is part of a multi-volume backup set, the Set ID is the media number of the first volume in the set.

Sequence

if this volume is part of a multi-volume backup set, the sequence number is the position of this volume in the set (e.g. ‘2’ if it is the second volume.) For a single volume backup, set Sequence to 1.

Press Accept to add this volume to the media table.

To label a volume

backup3G can electronically label backup tapes using details from the media table.

1. Select Drive from the backup3G button bar.
2. Choose the drive into which the tape or diskette will be loaded.
3. Perform Label > Write label
4. backup3G lists the numbers for all the media that are valid for this drive type. Choose a media number to be written to the label.
5. backup3G displays a warning that any data on this volume will be erased. You will be asked to confirm that you want to label it. You will also be warned if the volume is already labeled with a different number or if the selected number is already in use, but you will be able to proceed.
6. backup3G asks you to confirm that the volume is in the drive. Load it now if you haven’t already done so, and press Accept.

Caution Don’t label tapes that already contain data you wish to keep. 
The label file will overwrite the front of the tape, usually rendering the data on the tape unreadable.

backup3G confirms that the label has been written and verified.

A small file containing the media number is written to the volume, at the beginning in the case of a tape and at the end in the case of a diskette. The format of the label depends on the ‘label type’ defined for this media type. Any backup job that requests this media number will check that the label is correct before proceeding.

It is not necessary to label media when they are first added to the media database. If an unlabeled scratch volume is loaded, backup3G checks that this volume hasn’t already been used, and asks the operator to confirm whether it should be labeled now.

To read a media label

You may want to check the electronic label on a volume, for example if the paper label on the outside of the case falls off.

1. Select Drive from the backup3G button bar.
2. Select the drive name you want to use.
3. Select Label > Read label. backup3G prompts you to load the tape or disk into the drive.When the volume is loaded, press Accept.

Adding a New Media Type

Each unique storage format used for backup is stored as a media type. You can specify which media type a backup should be written to. For example, using the same drive, you could choose to do a full backup of a large filesystem to a 5–gigabyte Exabyte tape, and smaller backups to lower capacity 2–gigabyte tapes. As new formats become available you can add them to the ‘Media Type’ table and use them when defining backup jobs.

It is important to define the capacity and partition size for each media type that might be used to write multi-part backups. This information is used to split large backups efficiently over several parts or volumes.

To add a media type

1. Select Media from the backup3G button bar.
2. Select Maintain > Media type.
3. Select an existing media type with similar attributes, then select Table > Clone. If there are no similar media types, select Table > Add.

Enter the following fields:

Type

Enter the name of the media type you are defining.

Block size (KB)

Choose a blocksize that yields efficient backup and recovery performance. A smaller block size means more inter-block gaps, which slows the backup and reduces the effective capacity of the tape. Check the drive specifications to see if there are any limitations on the block size.

Length (feet)

the length of the tape. This is optional.

Density (BPI)

the density (in bits per inch) at which the volume is written and read. This is optional.

Capacity (KB)

the usable (formatted) capacity of the volume in kilobytes. This value is required to be fairly accurate if the volume is to be used for multi-volume backups. For diskettes, subtract 1 kilobyte to allow room for the end label.

Multi-part size (KB)

Backups can be written over several tape files or parts to speed recovery of selected files. This field defines a ‘part size’ that is some fraction of the capacity of a full volume.

Description

briefly describe the media type, indicating its capacity, density, part size, etc.

Label

type This determines what label format and method will be used to electronically label volumes:

COSstdtape

writes a short file containing the media number and ‘date last written’ to the start of the tape, and an end-of-data marker after the last file (recommended).

COSstdBOT

writes the label to the start of a tape, but doesn’t write an end-ofdata marker.

end_label

writes the label to the last block of a diskette.

sV_ filesys

System V filesystem label using the labelit command.

blank

volumes will not be labeled.

Press Accept to save this media type information.

Recording a Media Maintenance History

backup3G can record a history of preventive or corrective maintenance procedures. This is useful for judging when to retire a set of tapes, and for comparing the lifespan of different types and brands of storage media.

Note These options don’t actually do any physical maintenance; they simply record the fact that the maintenance was done.

Media maintenance facilities are found under backup3G configuration > Maintain tables. The ‘Media Maint Procedure’ table lists the maintenance procedures that can be performed. The ‘Media Maint Record’ table contains a log of maintenance procedures that have been performed.

To record a maintenance procedure on a volume

1. Select backup3G configuration > Maintain tables.
2. Select the ‘Media Maint Record’ table. backup3G displays the maintenance history for all media.
3. Select Table > Maintain.
4. Select Maintain > Add.

Figure 34 — Add media maintenance details prompt.

Number

Choose the number of the volume that is being maintained.

Date

When the procedure was performed.

Maintenance

Select from the list of known maintenance procedures. If none of the predefined procedures is suitable, you can add a new one to the ‘Media Maint Procedure’ table.

Person

Who performed the procedure? Default => the current user.

Press Accept.

How To Read Backup Media Contents

backup3G stores information about completed backup jobs in the media database, including:

• when the job ran
• which base directories were backed up
• which backup method was used.

To display details of all media in the media database

• Select Media from the backup3G button bar.

The initial view shows all media in the database. Other options on the View and Reports menus display a subset of the media database – for example, media at a specified location or scratch media.

Media contents

There are a few ways to browse media contents, depending on whether an online index exists, and on whether you want to print the output or go on to recover files:

Using the online index: if an index exists, you can either search for an exact file name or display a list of all media containing file names that match a pattern.

Using base directory information: for all backups, regardless of whether an index exists, you can browse high-level information about the contents of each backup medium. The media contents table stores the base directory for each step that wrote to the media set.

The starting point for all these options is the Recovery module:

• Search > Base directories lets you search the media contents database for selected backups on selected hosts
• Search > Files lets you search all online indexes for selected files on selected hosts
• Contents > Open lists base directories for a selected backup.

Once you have found the right backup, you can recover selected files and directories or the whole backup.

Search Media Contents for Base Directories

1. Select Recover from the backup3G button bar.
2. Select Search > Base Directories to display a form similar to that shown in Figure 35.

Figure 35 — Searching media contents

Base directory/pattern

Enter the base directory name if you know it, or press Choose to select from a list. You can also limit the search to the subset of directories that match a pattern such as a partial base directory name or a regular expression. For example, enter the regular expression /usr/l to match /usr/local, /usr/lib, /usr/lost+found, etc. Enter * and select Pattern type ‘filepat’ to list all base directories.

For more examples see Searching Backup Media.

Host

Enter the name of the host machine where the data was backed up from, or choose from the list of hosts. Leave this field blank to display backups for all hosts.

Written on or after

Limit the search to backups written from this date until today.

Written on or before

Limit the search to backups written on this date or earlier.

Pattern type

Select ‘filepat’ to treat the contents of the Basedirectory/pattern field as a shell file pattern. Select ‘regexp’

to treat the contents of Base directory/pattern as a regular expression.

Press Accept to initiate the search.

backup3G lists each media set containing a backup of a base directory matching the pattern, including its current location. You can recover selected directories in background or interactive mode from this list. If the list is long, use the Search function to jump to a particular directory by entering all or part of the name.

Search Online Indexes for Backup Files

You can search one index to display all the files in a media set, or search all the indexes to find files that match a given name or pattern.

Note Searching a large number of indexes can be very slow. Use a start and end date to limit the search to a shorter period.

backup3G lists details similar to that produced by the ls -l command, including the full path name, for each file name matching the pattern.

To search through all online indexes

1. Select Recover from the backup3G button bar.
2. Select Search > Files to display a form similar to that shown in Figure 36.

Figure 36 — Searching online media indexes

Filename/pattern

Enter the file name or some part of it. If you enter part of the name, backup3G will list all file names that contain those characters. See Searching Backup Media. You must enter at least a partial file name.

The type of matching is determined by Pattern type.

Base directory/pattern

Enter the base directory name if you know it, or press Choose to select from a list. Enter a pattern (e.g. part of a base directory name) to limit the search to a subset of directories. Leave this field blank to search all backups.

Host

Enter the name of the host machine where the data were originally stored, or choose from the list of hosts. This field is optional. If it is left blank, all indexes are searched.

Written on or after

Limit the search to backups written from this date until today.

Written on or before

Limit the search to backups written on this date or earlier.

Pattern type

Select ‘filepat’ to treat the contents of Filename/pattern and Base directory/pattern as shell file patterns. Select ‘regexp’ to treat them as regular expressions.

Press Accept to list all the file names that match the search criteria. Note that a file will appear once for each time it has been backed up – there may be several versions of a file spread over several media sets.

Note On labeled tapes, the label is contained in the first file on the tape.
Each backup step that writes to the tape creates additional files.

To list the contents of a single media set

1. From the Recovery console, choose the media set.
2. Select Contents > Open. backup3G lists each volume and base directory on a separate line.
3. Select the step that backed up the data you wish to recover; use Index > Open to list the contents of the backup step if an index was created. Use the Search function to look for an exact file name.
4. If more than one backup step wrote to the media set, the high-level directory for each one will be listed separately. Select each one in turn to list all files in the set.

You can create, delete and open any indexes that exist and recover selected steps in background or interactive mode from this list.