Mixed Drive Types in SL500 Array

[AlanTLR]

We currently have an SL500 Tape Library, that we've been slowly trying to move to convert all LTO3 drives to LTO4, but we've only managed to procure 2 LTO4 drives, so we now have 8 LTO3 drives and 2 LTO4 drives, with a tape library full of LTO3 tapes.  I would like to move some backups to LTO4.  Is there any way to split up the Volume Pools or Volume Groups, so that I can set certain policies to only use the LTO4 tapes with the LTO4 drives?

[Marianne]

The NBU Device Config wizard will probably add the LTO4 tape drives as hcart and add new STU for it. Change policies to use this STU.

There is no need for new pool, but you will have to change some tapes to match the density of the tape drives. Although the hardware supports using LTO3 tapes in LTO4 drives, NBU will only mount the tapes in the drive(s) if the densities match.

You might not be able to change the density in the GUI and will have to use vmchange from cmd.

Better if you can identify a range of media-id's that are unassigned, delete them, add a Barcode Rule to add this range to hcart density (and Scratch pool) and then Inventory the robot.

[Sriram]

That is correct !

What Marianne said is absolutely correct, no doubt.

If you still want to go more organized you can have a new pool for LTO4 alone.

- Sriram

[AlanTLR]

NetBackup added those drives as HCART, but so are the others.  There's only one robot listed, so when I try to create the new STU, i only have the one option for the HCART robot, which includes all drives within the library.

I could create a separate scratchpool of LTO4, but afaik, there's no way to tell NBU to select from a specific scratchpool for a policy.

However, if the LTO4 tapes will only go into the LTO4 drives, then I shouldn't have anything to worry about; Organization of "this policy goes to LTO4 and this policy goes to LTO3" is nice, but I'm more worried about failure due to LTO4 tapes going into the LTO3 drives.

[Marianne · Accepted solution]

If you have new LTO4 media, you will have to configure the LTO3 and LTO4 drives as different HCART types, and the same with the media. If you leave all as same density, NBU will try to assign LTO4 media to LTO3 drives. The robot will deny the mount request and you will end up with lots

I find it odd that your LTO3's are configured as HCART - that is not the NBU default. The wizard adds them by default as HCART3. The problem here is that all your media containing backups have the same density as the tape drives - it cannot be changed.

Your only choice now seems to be changing the LTO4 drive and media density to something else - your choices are HCART2 or HCART3.

When you have drives with a different density, you will be able to add another STU.
(STU groups together all drives of specific type, attached to the same media server, in same robot. So, new density = new STU. All other parameters - robot #, media server name - remain the same.)