Is there any technical reason tape backup is so expensive and out of reach for c... (2024)

The true cost of tape is that of the tape drive.

Tapes themselves are pretty darn cheap. LTO-5 tapes cost $25 for 1.5TB (uncompressed). Multi-layer Blu-Ray is the only solution that is anywhere close to that cheap... but those are a pain-in-the-ass to use. (You'll need Thirty 50GB Blu-Rays to do the job of a single LTO-5 tape)

Also consider: At x8, BluRays are written at 36 MB/s. Tape Drives are read/written to at 140MB/s, making them much faster than BluRays.

The problem is that tape drives cost roughly $2000 each. So tapes only become economical when you're storing 25+ TB of data.

For people who are used to ~20MB/s (maximum) off of x4 speed 50GB BluRay drives, I think the problem you note is a "first world problem"... a problem many people would be happy to have.

On no! My Tape Drives are written too fast that they're causing me issues :-). If only my hard drives were fast enough to keep the write buffer full!

I suppose so in some ways, but shoe shining will prematurely wear out your LTO tapes and drives.

The L in LTO is for linear: when the tape writes its traveling at over 100 inches per second. Compare to helical scan tape systems like VHS and DAT/DDS where the tape heads are moving very quickly past the tape but the tape itself is not really fast at all. So if the write buffer empties, the drive has to decelerate the tape, wind it back quickly, then accelerate it so it's at full speed when it's at the location to write a new block.

I might recommend DDS for the 3rd World ^_^. It's what I used until it fell too far behind hard disk sizes.

On the other hand, it doesn't make sense for "consumers" to chase the latest and greatest tape technology, for which there's always a price premium. Plus there's no single disk drive that's fast enough to feed a LTO-5 drive, which I'm sure extends to LTO-6. (Note, each generation of LTO drives will write one generation back and read two generations back.)

The latter wasn't available when I set my current home system (the limits of local disk back where firmly confirmed by this: http://www.ancell-ent.com/1715_Rex_Ave_127B_Joplin/images/), but LTO-4, which will hold 800 GB per tape before compression and which while perhaps obsolescent is still widely used (hits some nice price performance points), was and I think still is quite feasible, albeit costly. But then again, how much is your data and piece of mind worth to you?

HP 1760 drive is on the the slow end, but that's fine for consumers with much less severe time to backup and time to restore requirements. Newegg price is a bit above $2K, with some serious bargain shopping you should be able to get one for substantially less. Add at least one SAS adapter (I use two), I like the LSI 9211 line, and a -4i (4 internal ports, BTW, they work with SATA drives as well), current Newegg price $163, and a fast but small SAS drive for buffering, say a Seagate Cheetah or Savvio 15K drive of 146 or 300 GB size, Newegg has an anomalously priced Cheetah 300 GB at $168 right now, call it $200 plus or minus, and then of course media.

There you want to get serious about bargain hunting and bulk buying (5-20 tapes at a time), but Newegg's single quantity pricing for Fujifilm or HP tapes is $40 plus or minus 2, and fairly easy bargain shopping I just did on Amazon to buy a few tape found HP tapes at $24-25 each from high reputation merchants.

dragontamer at https://news.ycombinator.com/item?id=7699179 says LTO-5 tape is going for $25 each, which would match my experience with LTO-3 tapes costing about the same as LTO-4 when got my drive; I just use 9 tapes for Bacula incrementals and differentials for a while, then move them to the full pool.

If you're gonna modernize that setup, I'll have to say that a cheap SSD for buffering will negate any future issues. Cheap PCIe SSDs are almost here (the cheap PCIe Sandforce controller chip was just released... consumer-ready PCIe SSDs ought to be around in just a couple of years).

Its possible to max out the 6GBps channel (ie: 480MB/s) with say... a $90 120GB Vertex-3. (http://www.amazon.com/OCZ-Vertex-2-5-Inch-Performance-VTX3-2...).

The M.2 SSDs and PCIe SSDs are faster of course, which is why Consumer PCIe SSDs are getting pushed out by LSI and others. There isn't much point to faster SSDs when you're limited by the 6Gbps SATA port.

For example: $300 for the 240GB Plextor M6e, with read speeds measured at ~667 MB/s: http://www.newegg.com/Product/Product.aspx?Item=N82E16820249...

So SSDs are actually both cheaper, and more performant than a 15k SAS buffering drive!

http://techreport.com/review/26058/the-ssd-endurance-experim...

The TLC SSD (3-bits per cell) is showing minor issues after 600TB of writing, but is still a usable drive. The MLC (2-bits per cell) SSDs have shown no issues after 600TB.

In comparison, a tape-drive would have long-past its ~200 end-to-end reads rating. MLC SSDs wear out slower than a tape drive! (Please don't take this sentence too seriously. I know I'm using hyperbole)

The SSDs I've linked to are MLC (2-bits per cell) designs, and can be expected to have roughly the same endurance as the MLC SSDs that techreport is testing.

 By far the most telling takeaway thus far is the fact that all the drives have endured 600TB of writes without dying. That's an awful lot of data—well over 300GB per day for five years—and far more than typical PC users are ever likely to write to their drives.

Besides, the backing storage is Tape. You're only using the SSD as a temporary stop so that your writes can be buffered out all at once. Using an SSD as a caching option has been extensively tested! Its safe to use for this sort of thing.

I think that's a bit past hyperbole, that's 200 end-to-end "wraps" per tape cartridge. A tape drive is (in theory) a LOT more durable, my drive has an official MTF of 250,000 hours at a 100% duty cycle.

That said, at least for my purposes, using one such SSD drive as a 5+ year "consumable" would work just fine, and the price for the Intel 335 is just fine.

(On the third hand, since all my system "disks" are LSI RAID 1 2 disk mirrors, I had all the infrastructure to add a 3rd drive, and I trusted Seagate enterprise SAS drives more than I trusted SSDs of that class 3 years ago (not that the latter were big and durable enough back then, unless perhaps you went to the $$$$$$ enterprise level of SSDs drives), I use the drive for some other backup systems, like sending my most important data to rsync.net using rsyncrypto, so I need some speedy disk to disk action. When I do a major system refresh in 2+ years I'll seriously consider SSDs, or if I have to replace my LTO-4 drive before then and need to seriously look at LTO-5 drives and media; I just passed the 2 LTO-4 tapes per monthly full backup threshold....)

I remember prices just 3 years ago, and I can agree with you on that.

SSDs just have advanced surprisingly far in these past couple of years. Be on the lookout for PCIe SSDs on your refresh! They might be ready by then.