On Mon, 18 Jun 2012, Ken Teh wrote:
Hi all,
I need some help and advice with LTO tape drives. I haven't kept up with
tape technology for several years now and from a quick google, it appears
that the only games in town are LTO and DDS. We do have a single DDS
deployment and we are looking at replacing it with LTO because of capacity
limitations.
Some questions:
(1) It appears that LTO-5 is the current technology. But most single drives
use SAS as an interface. Again, I am not familiar with SAS. All I know is
what the acronym stands for. Is it a simple matter of buying a SAS card?
Will it run out of the box on a SL6.x box? Any issues with drivers?
(2) I see that LTO-4 is still available. And a quick google suggests that
Ultra160 or 320 LVD SCSI is the more common interface for these drives. I
have several of the Adaptec 29xxx cards, made available when we transitioned
to SATA. Is this viable or would you recommend against using LTO-4? It
appears to be about 5 years old. I think it would be preferable to use
technology that has at least some life to it but I am not inclined to work
very hard to make LTO-5 work if it is not well supported on Linux.
We are not looking to do anything fancy. A single internal drive and a box
of tapes. Backups the old fashioned way.
Specific recommendations welcomed. As in, buy this card, buy this drive!
We are using a Dell-provided LTO-5 library which appears to be a re-badged
IBM model... ie in /proc/scsi/scsi both the changer and the tape drive
show up as IBM models:
...
Host: scsi1 Channel: 00 Id: 00 Lun: 00
Vendor: IBM Model: ULT3580-HH5 Rev: A422
Type: Sequential-Access ANSI SCSI revision: 06
Host: scsi1 Channel: 00 Id: 00 Lun: 01
Vendor: IBM Model: 3573-TL Rev: 9.50
Type: Medium Changer ANSI SCSI revision: 05
...
We talk to it using a Dell-provided SAS card which is a re-badged LSI e.g.
from lspci:
...
04:00.0 Serial Attached SCSI controller: LSI Logic / Symbios Logic SAS2008
PCI-Express Fusion-MPT SAS-2 [Falcon] (rev 02)
...
This is automatically detected and seems to work fine with sl5.7, I've not
tested it with anything much older. (It seems to use the mpt2sas driver
from what I can tell).
So far we havn't noticed any problems though we are just going through
setting up and testing bacula with it (to replace an older setup with an
LTO-3 library on an sl4 box) so it hasn't had significant use yet.
-- Jon
