confusion on DLT/DLT2/DLT3

[jwmcf1]

Ok so after looking through a few discussions and through the admin guides I am still somewhat confused as to what DLT, DLT2, and DLT3 is exactly specifing within NBU.

Fact: I have two SDLT 320 drives which read SDLT1 media.  Now some confusion has come about as of late due to the fact that within NBU the drive type for these two SDLT 320 drives is set to DLT2.

Now the reason for the confusion is that SDLT600 drives use SDLT2 media so we have a situation where the DLT2 in NBU is being equated to SDLT2 media.

Now I'm pretty sure this isnt the case but it brings up the question of what is the purpose of DLT,DLT2,DLT3 drive types in NBU?

Is this simply a way of differintiating between two drive types as if I had a SDLT320 drive and a SDLT600 drive? If so I should be able to set these SDLT320 drives to DLT with no issues. Or does this setting determine compression/speed/other such settings for the drive?

And lastly (and I guess really the only question that needs answering)does DLT and DLT2 refer to SDLT1 and SDLT2 drives?

thanks 

[Marianne]

The different drive/media types are logical classifications. Once you choose a drive type in NBU, the media type has to match, otherwise NBU will not load the tape in the drive, even if the hardware supports different media types.

If you think about all the DLT tape drives out there - DLT4000, DLT7000, DLT8000, SDLT, etc. -  NBU allows you to use up to three of them in the same configuration. You choose which type to assign to which drive type, or allow the Device Config Wizard to decide for you.

The Device Config Guide will give you more info about this logical separation.

Extract from 6.5 Device Config Guide:

http://www.symantec.com/docs/TECH52800

Alternate media types
Alternate media types let you define more than one type of tape in the same library, and you want to differentiate between them. The following are examples of alternate media types:
■ 8MM, 8MM2, 8MM3
■ DLT, DLT2, DLT3
■ HCART, HCART2, HCART3

For example, if a robot has DLT4000 and DLT7000 drives, you can specify the following:
■ DLT media type for the DLT4000 tapes
■ DLT2 media type for the DLT7000 tapes
NetBackup then does not load a tape that was written in a DLT4000 drive into a DLT7000 drive and vice versa.
The drive types must be configured by using the same NetBackup convention.

[jwmcf1]

So that answers my question:

DLT and DLT2 is not a direct reference to SDLT and SDLT2, but is a means for NBU to track which tapes go in which drive.

So my question now is this:

Is media type a fixed variable?  What I mean is this: Is a SDLT I tape hard coded to be of media type DLT2?  A SDLT 2 tape always a DLTx and so on.

 OR

Is the media type assigned when media barcode is scanned or when loaded  by the DLT2 drive?

[Marianne · Accepted solution]

If you use the Device Config wizard, the drive type is determined by the Device Mappings file, external_types.txt.

http://www.symantec.com/docs/TECH129536

http://www.symantec.com/docs/TECH129535

For example, all of these drives will be configured as DLT2 when you use the wizard:

[DRIVE:NetBackup DLT2]

TECHNOLOGY_GROUP=NetBackup DLT
INQUIRY=DEC     TZ88
INQUIRY=COMPAQ  DLT4000
INQUIRY=Quantum DLT4000
INQUIRY=Quantum DLT4500
INQUIRY=Quantum DLT4700
INQUIRY=SUN     DLT4000
INQUIRY=TANDBERGDLT4000
INQUIRY=COMPAQ  DLT8000
INQUIRY=QUANTUM DLT8000
INQUIRY=TANDBERGDLT8000
INQUIRY=COMPAQ  SDLT320
INQUIRY=QUANTUM SDLT
INQUIRY=QUANTUM DLT-S4
TYPE=LEGACY
RW_DENSITY=NBU    DLT2

As far as media is concerned - if you only have one drive type in the robot and you do an inventory, all media will be added as the same type/density as the tape drives.

Media type/density is assigned when media is added to the NBU volume database - either via robot inventory or manually using the Media section of the GUI or via cmd using vmadd.

If you have more than one drive type in the robot, you should have different labels on the different media types. This will allow you to create Barcode Rules to assign tape ranges as specific media types before you do an inventory.

Extract from Admin Guide 1:

Note: For a robot that supports multiple media types, you should specify the density carefully.

This means that the backup admin needs to make this decision - even if you have a media type that can be used in more than one drive type, YOU need to separate them into different densities...

[jwmcf1]

Awesome!  That helps greatly.  Thank you very much.