Brian O'Neill wrote:

OK, I'm about to embark on setting up a new Legato server to replace our venerable Sun 450 with P3000 library. It is my first adventure with a VTL, and using staging/cloning to any great extent.

I've read many posts regarding setting up VTLs, etc., and I just want to gather all of it and see if I've got it straight, and pose a few extra questions while I wait for the hardware vendor to plug it all in.

For the hardware, the server is a Dell 1950 dual-core with FC and Ultra/320 SCSI PCIe boards and hardware-mirrored 300GB SAS drives.

The VTL is a Quantum DX3000 connected via FC - I forget the total capacity we ordered offhand.

The tape library is a Quantum PX502 with two LTO3 tape drives with SCSI connection. This will be used for staging to tape for offsite storage.

I plan to continue using Networker 7.2.2, although there are no plans to migrate the current saveset info - we'll start fresh.

==== VTL configuration

I understand people have been recommending configuring as many virtual tape drives as you can, and setting the parallelism for each to 1. Our current license (Network Edition) limits us to 16 devices, so that is our upper limit, which I don't think is a problem for us (I stagger backups).

Should I also set server parallelism to 16? I understand that regardless of device parallelism, it will add more sessions to drives if the server parallelism is set higher than the total.

I know this was to avoid multiplexing - but was this relevant to the VTL performance, restores, or was it more for staging later?

What advantages/disadvantages are there to choosing P1000 vs. P7000 vs. DX3000 emulation? Is the DX3000 as "supported" type in 7.2.2?

What about DLT7000 vs. LTO-2 for the virtual tape drives? DLT happens to be what we use now, but that should have no relevance here.

What is the purpose of defining empty bins? Is this just for virtual migration of cartridges?

==== Staging

I've done some D2D2T staging before, but only on a small scale. Given that I have LTO-3 drives, I know keeping write performance up is a consideration, and I don't need to use both drives at once - we got two more for redundancy.

We plan to keep our current schedule of moving tapes with the backups offsite on a weekly basis, so I would need to stage all (except perhaps the most recent) savesets to tape prior to removal.

I've used nsrstage manually, which "deletes" the old saveset, and I am aware of the automatic staging which stages based on age and/or space (although that may only apply to file/adv_file types?)

Ideally, I'd like to keep as much on the VTL as possible (for restore purposes), and still stage everything to tape for the weekly tape pull. We could do the staging once a week, or as needed - it doesn't matter. How best to set this up? I assume we'll have to set up cloning in some fashion - but how to we "expire" the originals on the VTL faster?

I think that's it for now.

-Brian

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