The NearStore VTL provides the following advanced configuration features. Some of these features simply need to be enabled, while others require additional configuration after they are turned on. The preface to the task instructions for enabling advanced features provides a description of the feature, as well as a link to any further configuration that might be required.

The NearStore VTL advanced features follow:

Use Customer (Customer Accounts)

You can use the NearStore VTL to create and manage multiple customer accounts. Each account has an administrator, who can manage the resources (virtual libraries and volumes) that you associate with the account.

This feature requires additional setup after you enable it. See the section called “Working with Customer Accounts” for more information.

Use Storage Pools

The NearStore VTL supports the use of storage pools, which are groups of disks that you can organize into specific storage resources. When you use storage pools with the NearStore VTL you can decide which virtual libraries use which disks. You do this by assigning your virtual libraries to storage pools when you create them.

Storage pools are useful for guaranteeing a separation of data (such as accounting and engineering) as well as enabling you to create high and low performance groupings of disk resources.

The NearStore VTL dynamically load balances across the available disks in order to achieve optimal performance. When using storage pools, the NearStore VTL load balances only across the disks in a specific storage pool.

The default behavior of the NearStore VTL is to group all disks into a single (called the default) storage pool.

This feature requires additional setup after you enable it. See the section called “Working with Storage Pools” for more information.

Enable Physical Tape Validation

When you enable the Physical Tape Validation option, the NearStore VTL stores a checksum for each physical tape that it imports. When a virtual tape that was created as the result of a physical tape import is exported, the NearStore VTL validates the stored checksum against the checksum of the physical tape to which it is being exported.

If the physical tape is the correct one, the export will continue. If it is not, the export will be paused and you will be prompted to load the correct physical tape into an available physical tape drive. This process helps to ensure that the wrong physical tape is not overwritten. Physical tape validation is the most useful when you are working with standalone tape drives.

This feature requires no additional configuration once you enable it.

Use Tape Pick List

Each time the NearStore VTL requires a tape that is not in the physical tape library, it will generate an action. This action requests that you load the physical tape, identified by a barcode, into an available physical tape drive or library.

When you enable the option to use physical tape picks lists, the NearStore VTL will also maintain a list of all physical tapes that need to be loaded into physical tape drives.

See the section called “Using Physical Tapes (Loading Physical Tape Drives)”.

Enable Host Access Control

If you want to restrict access to virtual libraries on a host-by-host basis, you can enable the host access functionality of the system. This will enable you to map hosts to virtual libraries. This function is also called Host access control.

These mappings can be either dedicated or shared. When the mapping is dedicated there is a one-to-one mapping between the virtual library and a host. This means that only this host can access the virtual library.

When the mapping is shared, multiple hosts share access to a single virtual library. You can separate the access control for the medium changer and each virtual tape drive when using shared access.

Enable Port Assignment

If the system has multiple front-end ports, you can map individual virtual libraries to one or more ports. You can also break a virtual library into its components (virtual tape drives and robots) and map each virtual device to one or more ports.

Enable this feature if you want to assign access to specific libraries to specific ports.

See the section called “Working with Port Assignments” for more information.

Enable Volume Set Addressing (HPUX)

Enable this feature if you are using an operating system that requires volume set addressing. For example, HP-UX requires volumes set address if it needs to see more than 8 LUNs. There is no further configuration required once you enable this feature. Note that Volume Set Addressing is a system-wide setting. If it is set, the NearStore VTL may no longer work correctly on hosts that do not support this mode of addressing.

Enable Shadow Tape

Enable this feature if you want to use the shadow tape feature. Once the feature is enabled , you can enable or disable the application of the feature on a per library basis. For libraries using shadow tapes, whenever a virtual tape is exported to a physical tape, the virtual tape is moved to the shadow tape pool. A tape in the shadow tape pool is invisible to the backup application, and is not listed as part of a virtual library, but is available for quick access if the physical tape is later imported, and is available for reading if the physical tape is stored offsite, or is otherwise unavailable.

Enable Over allocation

Without over allocation, the NearStore VTL automatically reserves enough disk space for any virtual tapes that you create. For example, if you create a virtual tape with a 40GB capacity, the NearStore VTL will reserve 40GBs of space for the virtual tape.

Because the NearStore VTL performs dynamic load balancing, it does not actually allocate space on a particular disk(s). Rather, the NearStore VTL reserves space from either a user-defined or the default storage pool. This means that the NearStore VTL automatically reserves enough space for each virtual tape that you create. It also means that you must have enough space available for each virtual tape that you create.

If you would like to create virtual tapes, even when you don’t have enough available disk space, you should enable the NearStore VTL over allocation feature. When this feature is enabled, the NearStore VTL allocates disk space to virtual tapes as needed, regardless of how many volumes you initially create. This feature is sometimes called Capacity on Demand.

Use Port 0d for Backend Devices

(Only displayed when a VTL700 or VTL1400 license is installed on the appliance.) When a VTL appliance has a VTL700 or VTL1400 license installed, the default configuration for port 0d is as a target port which you could connect to a host, but when you enable this option, and reboot the appliance, the port is configured as an initiator port, which you can then connect to a tape device.

Use ACSLS to control physical libraries

The NearStore VTL appliance can use ACSLS-controlled libraries. Set this option to enable the use of an ACSLS.

The ACSLS server and the VTL appliance communicate over a LAN, while the ACS tape drives communicate with the NearStore VTL appliance over the SAN. The NearStore VTL appliance does not communicate directly with ACSLS robot arms. Before configuring to use an ACSLS, make sure the LAN and SAN settings are correct.

The follow options require you to first set Use ACSLS to control physical libraries:

Enable EEP

When you enable EEP, the VTL can automatically manage the physical tape library entry/exit port (EEP) to move physical tapes to the port, and to move tapes from the port to appropriate slots. The next options provide additional controls on the movement of tapes to and from the EEP:

Enable Deferred Cloning

When you create a virtual library (Configuration Tasks > Virtual Libraries > Create Virtual Library), you can set the Enable Tape Cloning option (click More Options to see this option). With tape cloning enabled for at least one library, you can set the Enable Deferred Cloning option to allow a delay between specifying a tape cloning operation, and when the clone is actually created. See the section called “Using Physical Tapes (Loading Physical Tape Drives)”.

When you set the Enable Deferred Cloning option, you specify a span of time, during which the NearStore VTL will not create clones. Any changes that are made to the virtual tapes during this period of time will be held in queue until the deferred cloning time period has expired. At this point, these changes will be copied to the appropriate physical tapes.

When turned on, deferred cloning is applied to every virtual library in the system for which cloning is enabled. You cannot enable deferred cloning for only a specific virtual library.

Enabling Configuration Options

Complete the following to set advanced configuration options for the system:

A storage pool consists of one or more RAID group disks that are grouped together. Disk space for virtual tapes are drawn from storage pools. At its most basic level, a storage pool is created when the first RAID group is added to the NearStore VTL. This is called the default storage pool.

Unless the option to use storage pools is enabled, the NearStore VTL adds each additional disk to the default storage pool. Once you have added a disk to the NearStore VTL, you cannot move it to another storage pool.

When you enable the Use Storage Pool option, you can create multiple storage pools and then add physical disks to them.

You must enable the Use Storage Pools option before you can create storage pools and add physical disks to them. See Enabling Advanced Configuration Features for more information.

Storage pool tasks include:

All storage pool tasks use the Storage Pools List screen.

Complete the following task to view information about the storage pools, add a storage pool, or delete a storage pool:

Virtual libraries use virtual tape drives. Like virtual libraries, virtual tape drives are defined by type. The type of virtual tape drive used defines the capacity of the virtual tape that can be supported. The capacity of the virtual tape drive should match the native capacity of the physical tape drive to which you will be exporting data.

Because most physical tape drives compress data, you might want to enable the NearStore VTL smart sizing feature. When this feature is enabled, you can set the virtual tape drive type to support either LZS (STAC) or ALDC compression. See the section called “Using Physical Tapes (Loading Physical Tape Drives)”.

Default and Custom Virtual Tape Drive Types

The NearStore VTL comes with a number of default virtual tape drive types. These types can be used in virtual libraries. They can also be modified and used as the basis for custom virtual tape drive types.

Creating Virtual Tape Drive Types

Complete this task to create/edit virtual tape drive types: