Blind Libraries - Overview

Table of Contents

Overview

A blind library is a library without a barcode reader, and is the opposite of a sighted library which has a barcode reader.

Blind libraries can be configured using the Library and Drive Configuration window. During any library configuration the configuration process displays a prompt to confirm the presence or absence of a barcode reader in the library. If you indicate that the library does not contain a barcode reader, the library will be configured as a blind library. A blind library must have all its drives (and media) of the same type.

Once configured, a blind library cannot be converted as a sighted library.

Blind libraries have two distinctive features used by the MediaAgent software to identify media in the absence of a barcode reader. They are:

  • Library Inventory

    The MediaAgent software manages the media within a library by performing several types of inventory jobs to keep track of the slot numbers or drives in which the media are stored or mounted. For a detailed explanation of the inventory operation in a blind library, see Inventory Operations in Blind Libraries.

  • On Media Label (OML)

    Each media is initialized by writing an OML on the media when it is first mounted during the inventory/discover process. When the media is accessed later, the OML is used to validate and ensure that the correct media is mounted on the drive. (Note that for spare media in a sighted library, the new OML will not be created until the data is about to be written for the first time.)

Blind Library Operations

Most of the operations in a blind library are similar to the operations in a sighted library. The operations that are specific to the blind library are described in the following sections. For information on operations that are similar in both sighted and blind libraries, see Library Operations.

The following table lists the operations in the blind and sighted library.

Options Blind Library Sighted Library Additional Information
New Scratch Pool X X See Library Operations
Verify Media X X See Verifying Media in Blind Libraries
Discover Media X X See Discovering Media in Blind Libraries
Import Media X X See Importing Media into Blind Libraries
Export Media (with Verify option) X X See Exporting Media from Blind Libraries
Reset Library X X See Library Operations
Mark Library Fixed X X See Library Operations
Mark Media Exported X X See Library Operations
Inventory X   See Inventory Operations in Blind Libraries

Audit Trail

Operations performed with this feature are recorded in the Audit Trail. See Audit Trail for more information.

Inventory Operations in Blind Libraries

Several types of inventory operations in a blind library is used to identify, discover and search all or certain media in the blind library and to ensure that the slot occupancy and media identity are correctly associated in the CommServe database. The following inventory operations are performed in a blind library:

  • Full Inventory
  • Quick Inventory
  • Search Inventory

The above inventory operations are displayed as a job in the Job Controller window and can be killed if necessary. Information pertaining to the media discovered prior to the killing of the full inventory operation will be retained.

The system, by default uses all the drives in the library to perform the inventory operation. Similarly, the system tries to reserve drives for performing inventory operation, every 120 seconds.

For instructions, see Perform an Inventory Operation in a Blind Library.

Full Inventory

The full inventory operation may be initiated or scheduled by the user. The full inventory operation is used to identify the media used by the CommCell, initialize any new media, to prepare and update the media list in the library and to keep track of the location of the media within the library.

During a full inventory process, each of the media available in the library is mounted to read the OML.

  • If a valid OML is found, the media information will be associated with the slot occupied and updated in the CommServe database.
  • If a valid OML is not found, a new OML may or may not be created, subject to the criteria established for overwriting media in the library. For more information on the criteria for overwriting media, see the details for the Overwrite Media option available in Library Properties dialog box.

The full inventory operation may take several minutes, depending on the number of drives and the media available in the library. You must initiate a full inventory operation as soon as you configure a blind library and before you use the library for a data protection operation. You may perform a Full Scan of the library when you initiate a full inventory operation on the blind library. (See Full Scan for a detailed explanation on the full scan option.)

A full inventory operation is run with the lowest job priority, which means that it does not interfere with or interrupt other jobs that use the library. However, it is recommended that you run a full inventory operation when other jobs are not running or scheduled to occur. This ensures that the inventory operation utilizes all the available resources and completes the operation in the least amount of time.

A full inventory job can be scheduled and history information about the inventory can be viewed from the Admin Job History window.

Quick Inventory

The quick inventory operation must be initiated or scheduled by the user. A quick inventory operation is similar to a Full Inventory operation but is performed on only the newly occupied slots. Hence the quick inventory can be performed when you import new media into the library. (You may perform a Full Scan of the library when you initiate a quick inventory operation, (See Full Scan for a detailed explanation on the full scan option.)

During the quick inventory process, the system mounts the media from the newly occupied slots and attempts to read the OML on the media.

  • If a valid OML is found, the media information will be associated with the slot occupied and updated in the CommServe database.
  • If a valid OML is not found, new OML is created.

A quick inventory operation is run with the lowest job priority, which means that it does not interfere with or interrupt other jobs that use the library.

Search Inventory

When a job requests a specific media and if the media is not found in the original slot stored in the CommServe database, a search inventory operation will be initiated in the library to locate the media. The search inventory operation attempts to locate the media, by mounting and reading the OML from media in slot locations which were unknown or not confident. The search operation continues until the media is found. During a search inventory operation, new media will be initialized as in a Full or Quick inventory operation.

A search inventory operation is run with the highest job priority, which means that it will interrupt all Restartable jobs that use the library.

Full Scan

The full scan option must be used along with an inventory to check the media occupancy in the library slots and update the slot table in the CommServe database.

A full scan operation is recommended in the following situations:

  • When you export or import media directly through the library’s mail slot or when you open the library door and manually add or remove media or rearrange the media in the storage slots.

    It is therefore recommended that you initiate a full scan when ever you import/export media into a library, especially libraries without a mail slot.

  • When a Quick inventory operation fails to detect new media.

The library status is displayed as offline until the full scan operation completes. This means that new data protection or data recovery operations that access the library cannot start until the operation completes. A data protection or data recovery operation that is in progress when the full scan operation begins can continue as long as it does not need to access unmounted media.

Verifying Media in Blind Libraries

The verify media operation is a type of inventory which must be initiated by the user. This operation can be used to verify whether the media information displayed in the CommCell Console matches the OML in the media. There are two ways to initiate a verify inventory operation:

  • You can right-click a media and then choose the Verify Media option.
  • You can select the Verify Media option when you export the media or schedule an export (both from a list or based on a criteria). This option may be used to verify that the correct media is exported.

A verify inventory operation is displayed as a job in the Job Controller window and can be Killed if necessary. The verify inventory operation does not discover new media.

For instructions, see Verify Media in a Blind Library.

Discovering Media in Blind Libraries

Discover media is the process by which the MediaAgent software initializes new media and stores the media information in the CommServe database.

In a blind library the discover media operation is available only at the media level.

The discover media operation mounts the media into a drive and if a valid OML is not found, it writes the OML on the media. Once unmounted, the system also keeps track of the media location.

A discover inventory job is displayed in the Job Controller window and can be Killed if necessary. Also note that both the full and quick inventory processes will automatically discover new media whenever a new media is found.

For instructions, see Discover Media in a Blind Library.

Importing Media into Blind Libraries

Importing is the process by which you move media that are outside a library into storage slots within the library. The import media operation in a blind library is similar to that of an import media operation in a sighted library. (For a detailed explanation on importing media, see Import Media.) 

However, when you import media in a blind library, ensure that you perform a quick inventory with a full scan, in order to discover the imported media.

It is recommended that you initiate a full scan operation (if it is not automatically triggered) whenever you directly import media into a library, especially on libraries without a mail slot.

For instructions, see Import Media Into a Blind Library.

Exporting Media from Blind Libraries

Exporting is the process by which you physically remove one or more media from a library. The export media operation in a blind library is similar to that of an export media operation in a sighted library. (For a detailed explanation on exporting media, see Export Media.)

However, when you export media in a blind library, an option to verify the media is displayed, to ensure that the correct media is exported. Media that fails verification will not be exported. The media verification operation is not performed when the export media operation is scheduled.

When media is exported immediately from a blind library (not a scheduled export operation) the media export job is displayed in the Job Controller window and can be Killed if necessary.

It is recommended that you initiate a quick inventory with full scan operation (if it is not automatically triggered) when ever you directly export media from a library, especially on libraries without a mail slot.

Media Labeling in Blind Libraries

Automatic Labeling Schemes

The MediaAgent provides the facility to automate the process of labeling media (On Media Label - OML) in blind libraries. Several Labeling Options are provided to suit the labeling conventions used in your organization.

Care must be exercised while generating the labeling scheme to ensure that each media label is unique. If the specified labeling scheme is not unique, and if duplicate labels are found, the system automatically appends a media ID to make it unique.

Setting-Up Automatic Labeling Schemes

Use the following steps to setup the media labeling scheme in blind libraries:

  1. Specify the labeling scheme for a blind library, from the appropriate Library Properties (Media) tab. (For instructions, see Create Automatic Labeling Schemes.)
  2. The system will automatically stamp the label whenever a media inventory is performed.

Managing Cleaning Media in Blind Libraries

Cleaning media is automatically identified and moved to the Cleaning Media Pool when a full or quick inventory is performed.

However keep in mind that the cleaning media does not contain an OML and hence the system cannot differentiate each cleaning media, if multiple cleaning media are present. The cleaning media may get mounted whenever a full inventory operation is initiated which may result in the drive getting cleaned and the counters for drive cleaning reset.

For this reason we recommend the following:

Best Practices for Blind Libraries

Observe the follow guideline while using a blind library: 

  • Do not operate the library manually while an inventory operation is in progress.
  • Always request a full or quick inventory with full scan after you manually rearrange the media between the library slots or add or remove media directly (without exporting it first) from a blind library. 
  • Perform a Quick Inventory with Full Scan whenever you import media into a library. 
  • From the Media tab of the Library Properties associated with blind libraries, under the Start New Media pane, ensure that the When required media is exported option is enabled. 
  • As inventory and verify media operations have a lower job priority, make sure that at least one drive is free when these operations are initiated, especially when you need to import media for an active job.
  • Do not store cleaning media in a blind library. Import the cleaning media when it is required and export it after using it.
  • Label all the exported media for future identification.
  • Remove all the failed-to-be inventoried media, (i.e., bad, wrong format, write protected, etc.) from the library.