Library Properties - Overview
The MediaAgent supports a wide variety of storage units or libraries, which can be grouped into the following general categories:
|Library||Typically a multi-drive storage unit that houses multiple media cartridges for extended storage capacity. The physical size of the cabinet, generally determines the number of resident media drives and cartridges. Media movement operation inside the library is performed by a robotic arm, (or media changer) which is controlled by the library controller. Library can be tape.|
|Stand-alone drive||Typically a one-drive storage unit with no media storage capability. Media must be manually mounted (inserted) and unmounted (ejected) from the drive. It is also considered as a logical library.
Note the following:
|Disk Libraries||A disk library is a virtual library associated with one or more mount paths. The disk library does not represent a specific hardware entity; it is a software entity that contains a list of mount paths through which data can be sent to a disk media. See Disk Libraries for more information.|
The following sections describe the properties associated with tape/stand-alone drives. Note that all these options may not apply to all these libraries.
In the CommCell Console and in Books Online, all storage units are referred to as libraries, regardless of type.
The system initially assigns the library name which is derived from the library manufacturer and model. If necessary, you can modify the library name.
If you are using stand-alone drives, we strongly recommend that you physically label each drive using the library name shown in the configuration window. This will help you identify the proper drive when you are prompted to insert a cartridge into a drive.
The general information about the library, including the library manufacturer, model, firmware version, whether the library includes a barcode reader and the serial number of the library are displayed.
Product information includes information on the date and time at which the library was configured and the default scratch pool for the library.
Note that the default scratch pool is automatically created when the library and drives are configured. You can create additional scratch pools and designate them as the default scratch pool for the library. For comprehensive information on scratch pools, see Scratch Pools.
A timeout parameter determines how long a job waits for a status response after an operation is requested. If the job does not receive a success or failure status within the timeout period, the job is terminated and a failure message is displayed. You can set the following timeout periods:
The time period within which media must be moved to a drive and prepared for read/write operations.
The time period within which media must be returned from a drive to a storage slot.
See Modify the Mount and Unmount Timeouts for instructions.
You can use the space provided in the description box to record important and reference information about the library.
The status of the library indicates whether the library is online or offline, and if offline, the reason for the offline status. See View the Library Offline Reason for instructions.
You can use the enable/disable indicator to logically enable or disable the library. See Enable (or Disable) the Library for instructions.
You can enable this option when you wish to perform routine or other maintenance tasks on devices. This option is available in the MediaAgent, Library and Drive levels and you can appropriately enable them where needed.
Backup, Restore and Auxiliary Copy operations will not use the associated MediaAgent/Library/Drive, depending on where the option is enabled. However, other administrative tasks on the devices such as Full Scan, Drive Cleaning, Verify Media etc. can be performed, if required.
When this option is enabled, the system will automatically select an alternate resource (MediaAgent/Library/Drive) if Alternate Data Paths (GridStor) is enabled. If alternate resources are not available, backup, restore and auxiliary copy will remain in the Waiting state in the Job Controller and will automatically resume when you re-enable the appropriate MediaAgent/Library/Drive.
See Mark MediaAgent/Library/Drive Offline for Maintenance for instructions.
Other library characteristics such as the number of drives, slots, total number of media and empty slots, number of mail slots
The number of connectivity, status, mount and unmount errors in the library, and the last service time are also displayed.
See View the Storage Policies Accessing a Library for instructions.
Security allows you to associate a library with one or more CommCell user groups. For a detailed explanation of security, see User Administration and Security.
In a SAN environment, the library controller feature can be used to configure the active MediaAgent to automatically switch over to a failover MediaAgent, in the event of a failure in the active MediaAgent. For more information on library controllers, see SAN Attached Libraries.
The MediaAgent checks the library controller based on the value established in the Library Arm Controller failover interval in Minutes option from the Media Management Configuration (Service Configuration) dialog box available in the Control Panel.
Mark Media Appendable
When this option is enabled, a media will be marked as Appendable when it is not available in the library and a new media will be used by the job. (If this option is not enabled, the media will be marked as Full.) Enabling this option ensures that the media in the library is fully utilized.
In addition, the number of days within which the appendable media may be re-used can also be specified. Specifying the number of days prevents data belonging to backup cycles from being fragmented across several media, which also facilitates pruning of data and recycling of media in the library. Consider the following on reusing media that are marked as Appendable:
- Media marked as Appendable can be re-used only by the storage policy (and the same stream in the storage policy) that was previously used to write to the media.
- Media marked as Appendable will be re-used only when the currently Active media is either marked as Full or not available in the library.
- Appendable media will not be reused if an Active media was marked Full by a Synthetic Full backup.
By default, the Use Appendable Media option is enabled for 14 days for a library.
A media can also be marked as Appendable by the system under certain conditions. For a detailed explanation on when a media is marked as Appendable, see Media Status.
See Mark Media as Appendable for instructions.
Show Media Related Pop-Up Messages on CommCell Console
On stand-alone drives, to ensure that jobs have the appropriate media in place, pop-up messages are displayed when a wrong media or no media is available in the drive. These pop-up messages are displayed in the MediaAgent computer. You can enable this option to display the message in both the MediaAgent computer and the CommCell Console (irrespective of where it is open). See Pop-up Messages in Stand-Alone Drives for more information.
On stand-alone drives, when this option is enabled, the system will use a spare media from another scratch pool if the media is available in the drive.
Enabling this option ensures that data protection operations (and other write operations) continue smoothly when the media from the specific scratch pool is not available for the job. If this option is not enabled, the job will remain in the Waiting state, until the media from the specific scratch pool is made available in the drive. Appropriate Event messages are displayed in the Event Viewer. See Detecting Media Changes in Stand-Alone Drives for more information.
By default the Automatically use spare media from different scratch pool if found in drive option is enabled for stand-alone drives.
On stand-alone drives, when this option is enabled, the system will automatically unload the media from the drive when a different media is required. (If the stand-alone drive supports the automatic ejection of the media from the drive, the media will also be ejected.)
If this option is not selected, the system will not unload the media from the drive and will overwrite the media (when a job is initiated) if the Overwrite Media in drive if Media Not Written to in (n) Days/Hours is enabled, after the time specified in this option. See Media Operations in Stand-Alone Drives for more information.
By default the Unload media in standalone drive when different media is required option is enabled for stand-alone drives.
When the Assigned media is not available, either because it was exported or stuck in the drive, a new media can be used for the job by enabling the When required media is exported and When required media is stuck options.
Enabling these options ensure that data protection operations continue smoothly when the required media is not available for the job. If these options are not enabled, the job will remain in the Waiting state, until the assigned media is made available, either by importing or after it is manually loaded in the drive. Appropriate Event messages are displayed in the Event Viewer. See Start New Media for Data Protection Operations when Media is Exported and Start New Media for Data Protection Operations when Media is Stuck for instructions.
By default the Start New Media options are enabled for a library.
Another form of Start New Media option is also available for Data Protection and Auxiliary Copy jobs. See Advanced Backup/Migrate/Archive Options - Start New Media for more information.
Barcode Labeling Scheme
The options in this area provide you the ability to customize the media labels for stand-alone drives and blind libraries. (See Media Labeling in Stand-Alone Drives and Media Labeling in Blind Libraries for additional details.)
Virtual Mail Slot for Export
Virtual Mail Slots are use by Vault Tracker to store the media in a range of contiguous slots in the library. For comprehensive information on Vault Tracker, see Vault Tracker.
The media options for a library can be viewed or modified from the Media tab of the Library Properties dialog box.
See Set up the Virtual Mail Slots in the Library for instructions.
When Assigned Media Reappears in Library
The options in this area is useful to globally reset the container and/or export location associations for media, when a media is recalled or re-imported back to a library. These associations are viewable from the Media Properties - General tab. By default, these options are not enabled for a library. (See Recall Media, Export Media and Import Media for more information on the specific operation.)
See Reset Container and Export Media Location for Media in the Library for instructions.
- A media can be automatically overwritten when an error is encountered while reading the on media label (OML) by enabling the When Content Verification Failed option. If this option is not enabled, a mount error is displayed in the Event Viewer, when an error is encountered while reading the OML.
Caution should be exercised while enabling this option, as a valid media can be over written in certain cases. It is recommended that you enable this option to just overwrite a media that you know for certain can be overwritten. Once the specific media is overwritten, disable the option.
If this option is enabled and if a valid media with a different barcode is mounted by mistake, data in the valid media will be overwritten.
- Media containing data from other CommCells can be overwritten by enabling the When it is from a different CommCell option. If this option is not enabled, such media will be marked as Bad and moved to the Retired Media group. A mount error is displayed in the Event Viewer, indicating that the media is from another CommCell.
- On stand-alone drives, to facilitate the availability of media for data protection operations, you can enable the Overwrite Media if Media Last Written to in (n) Days/Hours option. This ensures that older media is used by the operation when a spare media or media marked as Appendable is not available in the library.
By default the Overwrite Media options are disabled for a library.
It is strongly recommended that this option be disabled at all times to prevent over-writing of data available in the media.
Do not enable this option on a library with mixed drive types.
See Overwrite Media with Old Data When Spare or Appendable Media is Unavailable for step-by-step instructions.
This option can be used on libraries that are shared between different backup vendors. When this option is enabled the MediaAgent will automatically prevent the usage of media associated with other backup vendors. By default this option is not enabled. Note that this option will be available only if the option to overwrite media When Content Verification Failed option is disabled.
As each backup vendor has a unique method of writing data on a media, the system can identify the media associated with specific backup vendors. Contact your software provider to obtain the list of supported backup vendors.
Enable Auto-Discover Media into default scratch pool
When this option is enabled, new media is automatically discovered whenever you import or introduce new media to the library. The new media is automatically moved to the default scratch pool.
If the option is not enabled, media must be manually discovered.
You can either enable or disable this option by default, during the library configuration process.
You can also enable the automatic discovery for cleaning media.
For comprehensive information on discovering media, see Discover Media.
Only use PnP disk when it is blank
Enabling this option ensures that blank disks with no other data is used for data protection operations and allows you to use disks exclusively for data protection purposes. (See Enable (or Disable) Option to Only Use Blank PnP Disks for instructions.)
Use disk only when the size is greater than (n) MB
Enabling this option and specifying the minimum disk size ensures that data protection operations use disks with a specific size. Depending on the size of your data protection operations, you can avoid using smaller disks which may result in a job spanning multiple disks.
See Enable (or Disable) Automatic Media Discovery for step-by-step instructions.
Auto Stamp Media in Drive
On stand-alone drives, when this option is enabled, the system automatically stamps a new label when an unidentified (or new) media is loaded in the drive. The system uses the specified Barcode Labeling Scheme or a default label to stamp the media. (See Media Labeling in Stand-Alone Drives for additional details.)
Stuck in Drive
The MediaAgent will attempt to recover media, that may be stuck in a drive, if the Enable Auto-Recovery option is enabled. By default this option is enabled. By default the MediaAgent tries to recover the media from the drive every 20 minutes. You can modify the frequency using the NAUTOSTUCKTAPERECOVERYINTERVALMIN additional setting.
By default, the Enable Auto-Recovery option is enabled in the library.
Attempt to remove media from the drive when unload fails
Similarly, the MediaAgent will use the move command to unmount media when the unload command in a drive fails if the Attempt to remove media from the drive when unload fails option is enabled.
You may want to enable this option if your library supports options to unload drive as a part of the move command.
By default, the Attempt to remove media from the drive when unload fails option is disabled in the library.
If the above options are not enabled, the drive status is displayed as offline, when a job encounters a stuck media or is unable to unmount the media from the drive. In such a situation, you must manually recover the media from the drive and then mark the drive online.
See Enable (or Disable) Stuck Media Recovery for step-by-step instructions.
The system automatically unmounts media that remain idle in the drive. This option allows you to specify the idle time after which the media should be unmounted from the drive.
In regular libraries, the media will be automatically unloaded when the media remains idle for the specified amount of time.
In stand-alone libraries the media will either be ejected from the drive or remain in the drive in the unloaded state (depending on the drive type) when the media remains idle for the specified amount of time. See Media Operations in Stand-Alone Drives for more information.
Mark Library/Drive Broken When Error Thresholds Exceeded
When a library exceeds the threshold values established for the library type in the Hardware Maintenance for a library, or when a drive in the library exceeds the threshold values established for the drive type, the system will mark them as Broken if you enable the Mark Library/ Drive Broken When Error Thresholds Exceeded option. By default the Mark Library/Drive Broken When Error Thresholds Exceeded option is disabled for a library.
Verify access path using Serial Number of Drive
Enabling this option ensures that the drive serial number and access paths are verified before reading or writing to the media. It is strongly recommended that this option be enabled at all times to prevent the overwriting of data, when the drive access path is changed due to hardware configuration changes.
By default, the Verify access path using Serial Number of Drive option is enabled in the library.
See Enable (or Disable) the Verification of Drive Access Path and Serial Number for step-by-step instructions.
Check for cleaning media loaded in Drive
When this option is enabled, the system always checks the media to see if it is a cleaning media, before performing any other operation on the media.
By default, the Check for cleaning media loaded in Drive option is enabled in the library.
It is strongly recommended that this option be enabled at all times. In most libraries, unselecting this option may result in SCSI failures which requires manual intervention to unload the cleaning media from the drive.
See Enable (or Disable) the Checking for Cleaning Media Loaded in the Drive for instructions.
Check for Tape Alerts
When this option is enabled, the system logs the drive errors (provided by the hardware manufacturers) while the drive is in use. The drive errors are logged into CVMA.log and CVD.log and can be used for troubleshooting the drive. By default, the Check for Tape Alerts option is enabled in the library.
See Enable (or Disable) the Logging of Tape Alerts for step-by-step instructions.
Set drive as needs cleaning on Cyclic Redundancy Checks (CRC) errors
When this option is enabled, the system automatically marks the drive as Requires Cleaning when drive reports CRC errors during read/write operations.
Skip Unload drive for Autoloaders before unmounting media
When this option is enabled, the MediaAgent skips the unload operation before unmounting the media from the drive. This can be enabled for libraries with autoloaders that automatically perform the unmount operation while unloading media. Typically you can enable this option on libraries, where unmount operations constantly fail with the error Operation failed as the source is empty. By default this option is not enabled.
Detect and update media type when media is loaded into the drive
When this option is enabled, the MediaAgent automatically detects the correct media type when the media is used the first time. For example, if you import mixed media in bulk and discovered them as a specific media type. (The media type information can be viewed from the Media Properties associated with the specific media.) This option is supported for IBM Ultrium and DLT/SDLT drives. By default this option is not enabled.
When this option is enabled, the MediaAgent automatically detects and update information pertaining to new drives that were replaced, during a subsequent mount operation. This option is supported on libraries that support drive serialization and also when a drive is replaced with the same drive type. It is strongly recommended that this option be enabled before replacing drives in libraries that support drive serialization as it provides a one touch solution for replacing drives. In some cases the system may not automatically detect the new drives. In such situations, follow the alternate procedures described in Hardware Changes to replace the drives. By default this option is not enabled.
See Automatically Detect Replaced Drives for instructions.
For STK libraries attached to ACSLS Server, you can enable the Use Drive ID for Drive Replacement in the Library Properties dialog box.
Check for media change in drive every n minutes
On stand-alone drives, when this option is enabled, the system automatically check the media in the drive to update the media information based on the specified minutes. See Detecting Media Changes in Stand-Alone Drives for additional details.
Enabling SCSI reservation prevents multiple MediaAgent hosts within a SAN environment from accessing the same drive concurrently. This option, when enabled, prevents the risk of data corruption by ensuring that the initiating MediaAgent has use of the drive exclusively during data protection and other operations. This option is useful in the SAN environment where multiple computers may try to access the same drive, resulting in data corruption.
Refer to the hardware manufacturer's documentation to determine if the target device supports SCSI-2 or SCSI-3 reservation. Enabling a SCSI standard that is not supported by the hardware may result in data protection job failures.
Both SCSI-2 and SCSI-3 reservations are supported. If supported across all Hardware, SCSI-3 would be the preferred setting. SCSI-3 has added benefits of Persistent Reservation features and preempting abilities. Before enabling either option, ensure the following:
- Verify that the target device supports either SCSI-2 or SCSI-3 command set for persistent reservation. Most tape drives are known to support either of these command sets.
- Inter-connecting hardware, such as storage routers or bridge, which connects standard SCSI devices into FC fabric, should also support this command. If you encounter any differences in behavior with this command, then identify the differences in the interconnecting components from the working host to non-working host. (Refer to the hardware manufacturer's documentation to see if this operation is supported.)
- When using SCSI-3 command set, make sure that the device drivers for the target device do not perform an implicit reservation. Some of drivers in Windows as well as on Unix are known to perform SCSI-2 reservation implicitly when the device handle is opened by an application. In this case the SCSI-3 reservation will fail with Reservation conflict, as SCSI-2 reservation is already active in the target. (Check the driver’s behavior using the documentation provided for the driver.) Notably, some IBM LTO family drivers and STK 9x40 family drivers are known to perform SCSI-2 reservation on Windows. On Unix, there are hooks to enable implicit reservation using a known interface through native drivers.
Use the ScsiCmdTool to test whether the hardware supports SCSI-3 reservation. See ScsiCmd Tool for more information.
SCSI-2 reservation is enabled by default for all tape drives attached to a newly installed MediaAgent in this release. When you upgrade a MediaAgent, SCSI-3 reservation will be enabled if it was enabled in the previous release. If SCSI-3 was not enabled, the SCSI reservation itself (which includes both SCSI-2 and SCSI-3 reservation) is disabled.
When these options are enabled, the cleaning tape is automatically mounted and a cleaning operation is initiated on the drive, whenever the selected options indicate that the drive requires cleaning. For comprehensive information on drive cleaning, see Drive Cleaning.
Automatically add datapaths for new drivepools configured
When enabled, the system automatically adds the alternate data paths for a shared library. It is also essential to enable the following option in the storage policy copy properties for this option to work: Automatically add new datapath option in the Copy Properties (Data Paths) tab.
This option can be used when several MediaAgents share a library. This will help you to automatically create alternate data paths in the associated storage policy during the library configuration.
When a library’s firmware is upgraded or when a hardware is replaced, sometimes it would start reading the barcodes of the media in the library differently by appending, pre-pending or truncating some characters in the barcode. When this option is enabled the system automatically updates the media barcodes in the library - both media inside the library and exported media. By default this option is enabled in the library.
Note the following assumptions:
- The length of the barcode for all media inside the library is the same.
- When the firmware is changed, the new string which is appended, pre-pended or truncated is the same for all the media. For example:
- There will be a difference in the length of the old barcodes and new barcodes.
If this option is disabled, and the barcodes are changed after a firmware upgrade all existing media, including media with data and spare media will be marked as exported and a new set of media (with new barcodes) will be listed inside the library. In this situation, you must update the barcodes as described in Manually Updating Media Barcodes after a Firmware Upgrade.
This option indicates whether the MediaAgent will reposition the tape and retry the read operation (i.e., data recovery operation, auxiliary copy operation, synthetic full job, etc) on SCSI errors, to prevent the failure of the job. You can also indicate how many times and how often the retry must be attempted.
By default the Retry read operations on SCSI errors option is enabled and the system tries to retry 5 times every 5 minutes.
Submit full scan on library when finding an empty barcode during drive unmount
Indicates whether a full scan of the library will be performed when an empty barcode is found while unmounting the drive. This is a troubleshooting option which can be enabled in a library if you constantly find that the system indicates that the media is exported when requested by a job, but physically found in the library. For the specific job to succeed, you must perform a full scan of the library. But if you find the problem occurring frequently you can enable this option. By default this option is not enabled.
The following parameters can be established under certain conditions based on the library. Note that changes to any of these parameters will take effect only when the library is Reset.
Prevent physical inventory of the library
This option provides the facility to disable the full scan operation initiated by the MediaAgent when there is a unit attention. (i.e., when the door is accessed, the mail slot is accessed, the library controller is reset, etc.)
In some older libraries, the firmware itself automatically initiates an inventory when there is a unit attention. If you notice that there is a double scan of the library after a unit attention, you can enable this option.
By default, the Prevent physical inventory of the library option is disabled.
Do Periodic mail slot check for any change in status
When this option is enabled, the MediaAgent will poll the library to see if there is any change in the status of the mail slot. Enable this option in libraries that do not automatically generate unit attention when there is a change in the mail slot. For example, when media is imported or exported and the mail slot is accessed to add or remove the media, the system will never know the status of the operation, unless this option is enabled. You can also specify how often the library must be polled by setting the Library Status Check Interval.
By default, the Do Periodic mail slot check for any change in status option is disabled.
Prevent Auto Import of Media from mail slot
When this option is enabled, media will not be automatically moved from the mail slot into the library. Instead the media will be moved only when an import operation is initiated from the CommCell Console.
We recommend that you enable both the Prevent Auto Import of Media from mail slot and Do Periodic mail slot check for any change in status options if you have a library which is partitioned into two or more logical partitions and the mail slot is shared by these logical libraries. This will ensure that the media is imported (or exported) to the appropriate library.
This option is also useful to control the import media operation using only the CommCell Console.
By default, the Prevent Auto Import of Media from mail slot option is disabled.
When this option is enabled, the library handler will issue a SCSI command during startup to unlock the library mail slot. By default this option is not enabled.
This option is useful when other software may lock the library mail slot and you would like the mail slot to be opened.
Library Status Check Interval
This option indicates how often the MediaAgent must poll the library to see if there is a change in the status of the library such as a change in the status of the mail slot, library door, library connectivity to the MediaAgent, etc.
If the Do Periodic mail slot check for any change in status option is enabled, this interval also indicates how often the MediaAgent polls the library to see if there is a change in the status in the mail slot.
Cartridge Access Port for Import and Export
If you have multiple mail slots in the library, the CAP ID associated with the mail slot that will be used for importing and exporting the media used by the specific MediaAgent. If necessary, you can also change the CAP ID if the specified CAP is busy.
See Best Practices for STK Libraries Attached to ACSLS Server for more information.
Operations performed with this feature are recorded in the Audit Trail. See Audit Trail for more information.