Tape Backup

August 22, 2006 9:21 AM

Sub $2k autoloading tape backup?

I'm looking for a recommendation on a good autoloading tape backup device.

It doesn't have to be windows / mac specific. The preference would be a rack-mounted stand-alone box with ethernet capability - but for under $2k - that might not be possible.

Thanks in advance for your advice!

posted by jazzkat11 to technology (12 comments total)

How much data do you need to backup?
posted by junesix at 9:50 AM on August 22, 2006

Cheaper, quicker and easier: Build a RAID array, using hardware RAID cards and large, inexpensive hard disks. I'd suggest using LSI RAID cards, and Seagate SATA drives (or other reliable hard drive) to build a 1Tb array, then build a network diff-based backup solution.

I have used the Amanda backup system before, and it works fine. You can also configure it to pretend that a disk drive (RAID drive, for example) is actually a series of tapes, allowing you to do a tape-like backup, but with the speed of a hard disk and the reliability of a RAID array. The system is called Virtual Tapes:

Amanda docs for the virtual tape changer

File Driver

I'd carve a 1Tb disk into 28 virtual tapes of 35Gb each, giving you a 4 week differential backup window. If you need more space per backup, perhaps 14x70Gb virtual tapes might suffice. Carve up to suit.

Amanda also gives you some really useful restoration features, that work perfectly happily with the virtual tapes, better than actual real tapes as the system doesn't have to wait for a tape changer.

You could probably put a box together for $800-$1000, then with the leftover cash build a second box to mirror the first one out to as a redundant backup, and a handful of spare disks for when one of the drives eventually breaks. LSI cards run on nearly every operating system available, so you get your own choice of OS.

Also, IMHO tapes are far too expensive, don't last that long and will invariably break when you need to recover some data. It's much easier to tell if a disk is broken, and you actually get some warning when it happens.
posted by gaby at 10:06 AM on August 22, 2006

junesix: It doesn't have to be anything too crazy large. Most of what will need to be backed up will be in the under 20gb range.

gaby: You basically just blew my mind. We have lots of harddrive space - and I could rig a 'virtual tape' system. It may be a good solution.

One concern I have is just pure simplicity of the tape. It's expensive, and space is limited, but if we need to offsite store tapes, for example, or if IT folks are out of town and someone needs to interface with it, the more simple the better.
posted by jazzkat11 at 12:00 PM on August 22, 2006

Repeat after me, children: "Discs are not a backup device".

If you haven't learned why yet, bless you.

If you don't have unmountable backups, you're not backed up.

I have a surplus ADIC 7-hole DLT-IV 20/40gb on my shelf; if you're interested, email's in the profile.
posted by baylink at 12:58 PM on August 22, 2006

Read what baylink said. Drives are nice, drives are fast. But they aren't a backup device.

Now email him for that ADIC machine ;) DLTIV tapes are cheap and plentiful. Whilst I can't speak for the quality of the robot (I worked for Quantum, not ADIC) the drive itself will basically never die.

Just don't (that is, do not) clean the drive unless it specifically asks for it. Overcleaning will wear away the head, and then you're up for a new drive.
posted by coriolisdave at 3:55 PM on August 22, 2006

I'd like to third the sentiment that hard drives are not a backup device. Think about it... there's two reasons to back up your data:

1) "Hard drives are unreliable." So why back up to another equally unreliable drive?

2) "I want offsite backups in case of a physical disaster." Hard drives are fragile, mechanical devices. Tapes are (relatively) hardy with no moving parts to speak of, certainly no delicate ones.

The third, I suppose, is to recover from unwanted changes or deletions. If it's a Windows server, look at Volume Shadow Copies. Better than tape for this purpose.
posted by CrayDrygu at 5:03 PM on August 22, 2006

Hrrm.

My server has 300g of files to backup on a full, ~20 gig each day. That is about 400g (it compresses slightly, so lets call it 330g). That is 9? DLT4 tapes (40/80 variety) per week.

$20/ea*9 = 180/week.

A maxtor 500gig usb harddrive is probably about the same. While I have a bad taste in my mouth for tapes (slow, etc) they are a great backup medium that lasts (whereas harddrives die, etc).
posted by SirStan at 6:24 PM on August 22, 2006

....or one LTO2 (200GB/400 compressed) cart, retails for less than $50 (australian, mind you, so $35? US).

DLT4 is, IIRC, about 15 year old technology. Of course you wouldn't use it for your (ie SirStan's) systems. LTO3 does 400GB native per tape.
posted by coriolisdave at 6:50 PM on August 22, 2006

On the HD vs. tape debate.. If you treat the hard drives like you would treat tape, they should be perfectly cromulent backup media. For example, plug in a external USB2 drive, run backup, unplug external drive, store in drawer or off-site. Of course that simplistic example would cause a lot of 10% full hard drives, which might end up costing more than tape..

Just to be clear, I don't have any experience doing this. On the other hand, if someone wants to claim that tape sitting in a drawer is more reliable than a HD sitting in a drawer, they had better do something to prove it - just saying so doesn't count.


gaby's system doesn't sound too bad, except you should probably integrate a backup rotation system of some sort, to get the reliability of off-line and off-site backup. Why not a simple online drive mirror divided up along the lines of gaby's suggestion, and then remove one of the two drives to off-line storage using some modified tape-rotation scheme? replacing the removed drive and restoring the array immediately, of course!

There must be references for this kind of arrangement..
posted by Chuckles at 6:59 PM on August 22, 2006

FWIW, of course, DLT IV is indeed about 15 year old technology...

and I'd bet dinner at Berns that there are a few thousand of those drives, minimum, out there churning away a backup every night, after being installed 15 years ago... and the original saves are still readable.

coriolis: nice choice of employers; DLT is *the best* tape backup technology I've *ever* worked with in 20 years; I don't think I've ever lost a tape, and only one drive failure.
posted by baylink at 6:16 AM on August 23, 2006

I've always found AMANDA to be a confusing pain in the ass. I wonder if it's improved any over the years.

Since disks are nice and cheap, why can't you do both? Dump stuff that might need to be restored quickly onto disk, and then dump everything onto tape and store it offsite.
A big problem with the "linux box with big drives" solution is something a friend ran into, painfully - if the RAID card dies, you might have a hell of a time getting the array back online. Disk to disk storage is nice, but is certainly no backup.

We're backing up a few terabytes of data (thanks to the SAN) every week on a mix of DLT & LTO3 using Legato Networker. I haven't had one single tape fail yet. The DLT drive unit is a StorageTek 9730 with 3 DLT 7000 drives in it.

You can find those units on eBay for a few hundred bucks Here's one with 4 DLT 7000 drives for $250. Those things last forever and work with pretty much every piece of backup software known to man.
The unit will back up 'round 2.5 terabytes by itself, iirc.

You never told us how much data you need to back up and also, what kind of data is it?
posted by drstein at 10:56 AM on August 23, 2006

baylink: Excellent. Although I'd guess you probably skipped investing in SuperDLT 320 drives, then.... ;)

IME, everythign up to SDLT220 was solid as a rock, particularly the DLT7000's -- there are gazillions of those out there, and they really never die. Particularly if you get one with the "new" tungsten head, which never wears. Kinda hard to tell which head it has without pulling the drive apart, though if you do check the label on the drive head -- if it ends with "P" (IIRC) it should be the good shit.

The 320 drives, however, seemed to suffer from what I assume was a rushed production cycle (an attempt to beat LTO2 to market). Everything I saw of them convinced me that LTO2 was a far more solid technology. I have no experience with the SDLT600s, though, so if anyone has the good word on those please let me know! :)
posted by coriolisdave at 4:00 PM on August 23, 2006