Repositioning of tape

HP LTO 4 Tape Media
HP LTO 4 Tape Media
In my past life, I worked for a dominant tape vendor. Over the years, we had heard a number of times that tape was dead. But it never happened. BTW, it’s also not happening today.

Just a couple of weeks ago, I was at SNW and vendor friend of mine asked if I knew anyone with tape library expertise because they were bidding on more and more tape archive opportunities. Tape seems alive and kicking for what I can see.

However, the fact is that tape use is being repositioned. Tape is no longer the direct target for backups that it once was. Most backup packages nowadays backup to disk and then later, if at all, migrate this data to tape (D2D2T). Tape is being relegated to a third tier of storage, a long-term archive and/or a long term backup repository.

The economics of tape are not hard to understand. You pay for robotics, media and drives. Tape, just like any removable media requires no additional power once it’s removed from the transport/drive used to write it. Removable media can be transported to an offsite repository or accross the continent. There it can await recall with nary an ounce (volt) of power consumed.

Problems with tape

So what’s wrong with tape, why aren’t more shops using it. Let me count the problems

  1. Tape, without robotics, requires manual intervention
  2. Tape, because of its transportability, can be lost or stolen, leading to data security breaches
  3. Tape processing, in general, is more error prone than disk. Tape can have media and drive errors which cause data transfer operations to fail
  4. Tape is accessed sequentially, it cannot be randomly accessed (quickly) and only one stream of data can be accepted per drive
  5. Much of a tape volume is wasted, never written space
  6. Tape technology doesn’t stay around forever, eventually causing data obsolescence
  7. Tape media doesn’t last forever, causing media loss and potentially data loss

Likely some other issues with tape missed here, but these seem the major ones from my perspective.

It’s no surprise that most of these problems are addressed or mitigated in one form or another by the major tape vendors, software suppliers and others interested in continuing tape technology.

Robotics can answer the manual intervention, if you can afford it. Tape encryption deals effectively with stolen tapes, but requires key management somewhere. Many applications exist today to help predict when media will go bad or transports need servicing. Tape data, is and always will be, accessed sequentially, but then so is lot’s of other data in today’s IT shops. Tape transports are most definitely single threaded but sophisticated applications can intersperse multiple streams of data onto that single tape. Tape volume stacking is old technology, not necessarily easy to deploy outside of some sort of VTL front-end, but is available. Drive and media technology obsolescence will never go away, but this indicates a healthy tape market place.

Future of tape

Say what you will about Ultrium or the Linear Tape-Open (LTO) technology, made up of HP, IBM, and Quantum research partners, but it has solidified/consolidated the mid-range tape technology. Is it as advanced as it could be, or pushing to open new markets – probably not. But they are advancing tape technology providing higher capacity, higher performance and more functionality over recent generations. And they have not stopped, Ultrium’s roadmap shows LTO-6 right after LTO-5 and delivery of LTO-5 at 1.6TB uncompressed capacity tape, is right around the corner.

Also IBM and Sun continue to advance their own proprietary tape technology. Yes, some groups have moved away from their own tape formats but that’s alright and reflects the repositioning that’s happening in the tape marketplace.

As for the future, I was at an IEEE magnetics meeting a couple of years back and the leader said that tape technology was always a decade behind disk technology. So the disk recording heads/media in use today will likely see some application to tape technology in about 10 years. As such, as long as disk technology advances, tape will come out with similar capabilities sometime later.

Still, it’s somewhat surprising that tape is able to provide so much volumetric density with decade old disk technology, but that’s the way tape works. Packing a ribbon of media around a hub, can provide a lot more volumetric storage density than a platter of media using similar recording technology.

In the end, tape has a future to exploit if vendors continue to push its technology. As a long term archive storage, it’s hard to beat its economics. As a backup target it may be less viable. Nonetheless, it still has a significant install base which turns over very slowly, given the sunk costs in media, drives and robotics.

Full disclosure: I have no active contracts with LTO or any of the other tape groups mentioned in this post.

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