Data Domain - Virtual Tape Library Configuration

Whilst the majority of users will only use OST with a Data Domain unit there are times when a VTL configuration may need to run in parallel with OST defined storage or indeed on its own.

NetBackup will treat a Data Domain VTL exactly the same as a physical library although it is likely that there will be less media management involved with a VTL than an actual physical library.

The VTL service must be running on the Data Domain before the configuration can start

# vtl status

If the VTL service is not enabled then it needs to be started

# vtl enable

Prior to creating the VTL configuration on the Data Domain it is assumed that the NetBackup media servers which will be writing to it have the correct zoning in place. If the Data Domain has an even number of HBA ports then it is  recommended that they are split evenly across the SAN fabrics, i.e. 2 HBA ports are connected to the A fabric and 2 HBA ports are connected to the B fabric. Likewise, when configuring the VTL tape drives it is recommended that an even number of drives are presented on each fabric to the host i.e. 2 drives presented on the A fabric and 2 drives presented on teh V fabirc.

The high level steps in configuring the VTL are

- Create the VTL

- Add tape drives

- Add a pool to hold the tape cartridges

- Add cartridges

- Create an access group

- rename HBA WWPNs for meaningful aliases

The following command will create a VTL, named VTLTEST, with 2 CAPs and 3000 slots. The number of slots created will determine the number of cartridges which can be created. The number of slots can be increased at any time up to the maximum number allowed for the model of VTL in use. The VTL will be TLD controlled within NetBackup. The model of VTL given is RESTORER_L180

# vtl add VTLTEST model RESTORER_L180 slots 3000 caps 2

Create the number of drives required, in the example below 8 LTO4 drives are created, again this number can be increased up to the maximum number allowed at any time

# vtl drive add VTLTEST count 8 model HP-LTO-4

Create a pool to hold the cartridges, otherwise they will be held within the Default pool. In the following command a tape pool called DATA is created

# vtl pool add DATA

Once the pool has been created then cartridges can be created, The command below will add 100 cartridges of type LTO4 with a capacity of 400GB per cartridge to the DATA pool. The barcode for the first cartridge will be B00000 and the barcode for each cartridge will increment by 1 until all the cartridges have been created.

# vtl tape add B00001L4 capacity 400 count 100 pool DATA 

When cartridges are first created they are placed in the VTL VAULT and need to be imported into the VTL. The cartridges need to be imported into the VTL library before they will be visible to NetBackup

# vtl import VTLTEST barcode B00000L4 count 100 pool DATA

Access to the VTL tape library must be set up for both the robotic changer, which will enable NetBackup to control the library and the tape drives. Access is configured via access groups. An access group should contain the server's initiator and the VTL devices which the server will access via that initiator such as tape drives or the robotic changer.

 

The access group should be given a meaningful name so it easy to discern what it is being used for.  As an example to create two access groups for a host called NBUSERVER which will be used for the host's HBA initiators in the A and B fabric use

# vtl group create AG_NBUSERVER_A

# vtl group create AG_NBUSERVER _B

The administrator needs to ensure that the zoning of the NetBackup media server ports has been completed. When a media server has been zoned to a Data Domain target FC port the WWPN of the media server should be given an appropriate alias clearly designating what the WWPN is

To create an alias for the host NBUSERVER's WWPN on the A fabric 

# scsitarget rename WWPN NBUSERVER_A

Once the alias has been created it can be added to the relevant access group

# vtl group AG_NBUSERVER_A initiator NBUSERVER_A

# vtl group AG_NBUSERVER_A initiator NBUSERVER_B

In this example the changer and 2 drives will be added to the AG_NBUSERVER_A access group and 2 drives will be added to the AG_NBUSERVER_B access group. The administrator will need to confirm the Data Domain endpoints (target HBA ports) which the server has been zoned to. The primary-port is the port on which the devices will be made visible, the secondary port would only be used in the event the primary-port was unavailable. 

# vtl group AG_NBUSERVER_A vtl VTLTEST changer primary-port 4A secondary-port none

# vtl group AG_NBUSERVER_A vtl VTLTEST drive 1-2 primary-port 4a secondary-port none

To double check the configuration of the access group use

# vrl group show AG_NBUSERVER_A

To erase a tape – be careful as this will not check if valid images are present on the tape before erasing it.

# bplabel -erase -m <barcode> -d <density> -p <volume_pool> -host <media server to perform the erasure>

The bplabel command will mount the tape onto a tape drive visible to the specified media server and erase the tape header, hence you will see the erase job within the NBU job DB.

To add a barcode rule

# vmrule -add <barcode_tag> <media_type> <volume pool> <max mounts> <description

To add a rule so that all barcodes with a first character of “T”, a density of HCART2 and no maximum mounts are added to the scratch pool, use :

# vmrule -add T hcart2 Scratch 0 "Data Tapes"

To delete a barcode rule

# vmrule -delete <barcode_tag>

# vmrule -delete T