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Best practices for setting up Dell VTL Container or NetVault Backup native virtual tape library (nVTL)

Using and managing a NetVault Backup nVTL on a DR Series appliance

General guidelines and best practices for using a NetVault Backup VTL on a DR Series

appliance:

• Only create enough media to cope with one full cycle of backups and the relevant

retention policies.

• Set the Automatically label BLANK media parameter to o (clear the check box) to prevent

erroneous use of blank media and to ensure ecient use of available media within a tape

pool. A tightly managed tape pool will ease the space-reclamation process.

• To simplify the management of tape pools, pre-label media and assign a NetVault Backup

media group label. Tapes will be reused properly within a tape pool and space reclamation

can be performed in an orderly fashion.

In our sample NetVault Backup VTL, we can now look at grouping the data that is to be

backed up to work with media groups as target sets. For example, if we have 2TB of data to

back up, the backup is processed on a weekly Full Backup basis, and the retention is 4 weeks,

we need 8TB of media. With media at 100GB each, 80 pieces of media can be added to the

target media group. The main reason for using media groups is so we can force the DR Series

appliance to reuse media before using blank media.

NetVault Backup’s media selection algorithm is:

• Target media in a drive

• Target media in a slot

• Target blank media

• Target media marked for re-use

As you can see, blank media would be used before media marked for reuse. If we do not

reuse media, the DR Series appliance will never be able to recover the space. By reusing

media, NetVault Backup overwrites the previous contents after the header has been updated

and reuses available space that otherwise would not be reclaimable by the clean cycle of the

DR Series appliance. Keeping spare media that is not grouped blank will keep the usage of

the DR Series appliance unit as low as possible.

Because the Automatically label BLANK media option is disabled, the backup may run out

of media before it completes, especially if the data set is growing. This is the trade o when

using a DR Series appliance; media management becomes necessary to ensure best use of

the unit.