Data backup is a universal issue with which all enterprises, from the largest members of the Fortune 500 to the SMB down the street, must contend. Backing up to tape is the standard solution to this dilemma. There is, however, much variance in available standards and options. This week, Hardware Today returns to its Server Room Components focus with a breakdown of backup options suited for enterprises and SMBs.
Gartner Vice President and Research Director Nick Allen sees most of the action in the tape drive market coming from the high-end midrange segment. "Far and away the strongest player there is IBM," he says. Gartner's 2003 market share statistics back this up. IBM and HP dominated, cornering 25 percent and 21 percent of the market, respectively. Storagetech and Quantum followed closely with shares of 17 percent and 16 percent, in that order. Certance (formerly Seagate) took 9 percent, and Sony captured 7 percent. SMB-focused Tandberg and Exabyte capped off the market, registering 2 percent and 1.3 percent, respectively.
LTO and SDLT Square Off
In the active high-end midrange space favored by the enterprise, two formats compete for tape dominance: Ultrium LTO (Linear Tape Open) and Quantum's SDLT (Super Digital Linear Tape). IBM, HP, and Certance worked together to develop LTO in 2000. LTO tapes can store 200 GB of data with 2-to-1 compression. LTO's successor, LTO-2, was introduced in April 2003 and doubles that 400 GB compressed, while retaining backward compatibility with earlier LTO-1 drives. LTO-1 drives can transfer 30 MB of compressed data per second, while LTO-2 drives move compressed data at 60 MB per second. HP's LTO-2 flagship, HP Ultrium 460, is priced in the high-$,5000 range.
Although SDLT is often lambasted as a one-vendor pony, Quantum has kept it competitive. Its latest release, the SDLT 600, stores 600 GB compressed. It moves it at 72 MB per second, retains some backward compatibility to the DLT format, and is priced in the $4,000 to $6,000 range, similar to the LTO-2-based drive.
"Depending upon when you measure it, LTO is outshipping DLT/SDLT 2-to-1 or 1.5-to-1," Allen says. Dissatisfaction with SDLT's DLT predecessor is one reason for LTO's success. "In my user base, somewhere between 75 percent and 80 percent of the DLT users were fundamentally unhappy," Allen said.
But Allen notes a silver lining. "Another 25 percent to 30 percent said, 'Hey, this did just fine, I'd like to have some read compatibility with my existing DLT.'" Another boon for SDLT emerges at the mechanical servos level. (Servos are what reads and error corrects data from tapes.) SDLT uses an optical servo, while LTO uses a magnetic one. SDLT is advantageous for highly security-minded companies, like law firms, where degaussing tapes for security purposes is a matter of policy. "If you degauss an LTO tape, you wipe out the [magnetic] servo, and you can get it re-servo'd but it costs money," Allen said. With the SDLT's optical servo, "you can degauss it, and it's happy."
Extreme Tape Testing
Exabyte and Tandberg Data also tout LTO and SDLT drives to the enterprise, respectively, but also aim other format drives at a lighter slice of the market
|Tandberg's SLR140 Backup Drive|
Exabyte positions its lower-end VXA packet technology against competitors like Sony with its DDS-4 (Digital Data Storage 4) or Tandberg's SLR drives. Priced at $999, the VXA-2 drive stores 160 GB of compressed data, which it moves at 12 MB per second. Exabyte's much-talked-about VXA technology writes and reads data in packets to dodge the tape alignment contingencies typically associated with linear data transfer to create a more robust solution. To prove this, Exabyte and its customers test tapes by, in effect, torturing them and then restoring from them.
"The harshest [tests] that we've done ourselves have probably been [tapes] dunked in coffee," Kieran Maloney, general manager of VXA Business Unit told ServerWatch. That test pales, however, in comparison to a test an Exabyte OEM customer employed. The customer pumped volcanic ash into a dust chamber with an Exabyte drive in an attempt to test until failure. "The VXA drive just kept on running for two weeks, and was reading and writing while [pumping] this volcanic ash in there 24 hours a day, and it never broke," Maloney said. After two weeks, "they just could not cause it to fail."
Tandberg also aims for robustness, but steers clear of the extreme sports tape testing approach. "I suppose we could play those gimmicks; I don't know why we would," said Ken Cruden, COO for Inostor (a subsidiary of Tandberg that represents the Oslo-based company in the United States). Tandberg handles problems of alignment by building more facilities into the SLR tape cartridge itself. "Both the supply hub and the takeup hub are within that cartridge and the tape path," Cruden said, "so you insert that in the drive, and you get a locking position relative to the head." This results in fewer moving parts and "extreme reliability," which is evident by an error rate of less than 1.5 percent. Cruden describes this as "the best in the industry." The SLR 140 is one of Tandberg's products. It holds 140 GB of data, which it moves at 12 MB per second compressed. It is priced in the $1,700 to $2,000 range.