Slashdot Mirror
Hard Drives Instead of Tapes?
An anonymous reader writes "Tom's Hardware News weekly news letter has a very interesting article about Dr. Koch of Computertechnik AG who won the contract to build a RAID backup system for the University of Tübingen. Dr. Koch took several standard entry-level servers, such as the dual-Athlon MP, and add modern components and three large-caliber IDE-RAID controllers per computer, and a total of 576 x 160GB Drives."
This is a much better solution than tape, really. It's predictable that the industry will probably move in this direction, now that the hardware is cheap enough and of high enough capacity to serve this function.
Imagine: instant recovery. Your backup could be a usable image of your live server.
One thing about tape systems that I didn't see mentioned was the portability of the media. Data recovery is still impossible if your backup burns up along with your server. I don't see anyone rolling one of these out to the offsite storage.
Maybe you could do it with a big pipe between your backup location and your servers. But I bet that would cost a bundle in bandwidth.
Also did anyone notice that typo on UPS (maybe they were on drugs USP)! It took me a good minute to catch it.
"I'm just here to regulate funkyness." - James Gandolfini, as Winston in The Mexican
Right now, Sony is shipping Super-AIT tapes. The cartridges are about 3/8 of an inch thick, and each holds 500GB, before compression (which is integrated in the drive hardware). The drive can read or write at 30MB/s, before compression. With typical IT compression of 2:1, you get just under 60MB/s. The cartridge goes for about $150. Just try and get a terabyte of disk for that much. No, the drives aren't cheap, but they get paid off quickly.
Yes, disk is good if you need instant access to your backup, and for small installations of under a couple of TB, using disk backups make sense, but for larger data pools, tape is far more economical.
Also, as mentioned in the article, disk is terrible if you need off-site backups. In addition, a tape library consumes far less power, takes up less space, and produces less heat than a drive array of the same capacity.
Basically, the death of tape has been predicted for years, but it hasn't happened yet.
Instead of building a giant kluge, why didn't they buy a few Quantum DX-30s? Each one only takes up 4U, holds 20 drives, and the internal software emulates a tape library so it easily integrates with enterprise backup software from Legato or Veritas. If your environment requires off-site storage, you could attach a tape library to clone the backups and then store the tapes off-site.
As someone who works in IT in the financial industry, let me tell you a little bit of what kind of requirements we fulfill. First of all, every system is backed up on a regular basis. For critical systems (systems that handle account numbers in any way), that schedule is daily or even hourly.
All systems have live fail-overs. When not required by law, and they frequently are, such systems are required by the demands of profit. If financial transactions falter for a *second*, it means money lost.
Back-up media is triple redundant and incremental over 5 days. Backup irregularities of any kind are logged, investigated, and acted upon by at least 3 individuals.
Copies of backups are stored both on site and off-site in a secure location provided by our insurance provider. We make frequent trips to this secure location daily in order to deposit backups. These procedures are audited and reviewed on a regular basis by both internal auditors and regulatory board auditors.
Tape is just a little more reliable than IDE in this kind of situation. Tape is going to be more recoverable, even in case of a long drop or serious auto accident between point A and point B. If necessary, teap will also survive shipping better.
Sorry, guys. As reliable as IDE drives have become, they're just not as durable as a tape cartridge. With the sheer amount of backup we keep, it's also significantly cheaper.
The next Slashdot story will be ready soon, but subscribers can beat the rush and slashdot the links early!
Etched stone seems to have a staying power of approximately 10,000 years, even with some outdoor exposure.
Earthenware tablets, made of clay fired at low temperatures (1816F/991C), seem to do nearly as well, while stoneware tablets, made of clay fired at high temperature (2345F/1284C), last about the same as actual stone. Ceramics have relatively high resistance to moisture and thermal variation. Depending on the clay composition and the application of glazes, there is variable resistance to acid. Ceramics do not handle physical shock particularly well.
Glass can last thousands of years, but is vulnerable to shattering or acid.
None of these, however, are earthquake-resistant. Outside of the immediate blast radius, they're good against nukes.
Etching into stainless steel is good, although in the event of a nuclear attack, this would be succeptible to melting (or self-destruction due to induced current) within a certain area. It handles thermal and moisture extremes pretty well, but doesn't handle acids well.
Stamping into gold foil is expensive, but quite durable. It's immune to some of the chemical risks posed by steel, but is more likely to be stolen. It's also not as hard, thus leading to risk of data corruption or loss via impact.
Parchment, preserved lamb or sheep skin, can last a very long time (on the order of 2,000 years) in the right conditions. It does well with exposure to electromagnetic radiation, but deals badly with moisture or excessive dryness, and is highly vulnerable to acid.
Delay-line broadcast (reflecting your data with a laser off of a distant object, and rebroadcasting ad infinitum) is fairly reliable until occlusion of the data path occurs, or the transceiver is smashed, unplugged, EMPed.
Yeah, data preservation is hard in the long haul.
Eloi, Eloi, lema sabachtani?
www.fogbound.net