By Dave Simpson
Despite all the talk about disk-based backup, the tape industry appears to be on a minor rebound after three years of decline. That's according to the recently released Compact Tape Outlook report from Freeman Reports, in Ojai, CA.
The 240-page report covers a variety of tape technologies and formats, including cartridge (Travan, SLR), DAT (DDS), 8mm (Mammoth, VXA, AIT), SAIT, DLT/SDLT (including "value" DLT drives such as VS80 and VS160), and LTO Ultrium (see figure, p. 34).
The hottest growth segment of the compact tape market is in so-called "super drives" (100GB or more per cartridge), which includes LTO, SDLT, and SAIT. And among those, LTO has the most momentum in terms of end-user adoption.
For example, although the overall compact tape drive market shrunk by 4% in 2003 due primarily to rapidly declining sales in the desktop and entry-level segments such as Travan, SLR, DAT, and low-end 8mm and DLT drives, increased sales of super drives nearly offset those declines. For example, LTO drive shipments jumped from 175,000 units in 2002 to 262,000 in 2003, while shipments of SDLT drives increased from 109,000 units in 2002 to 152,000 units in 2003 (see table).
Although LTO shipments are outpacing SDLT shipments, Quantum's relatively new SDLT 600 drive now boasts a higher native capacity than LTO-2—300GB versus 200GB (see figure, bottom right).
According to Bob Abraham, author of the Freeman report, several factors are fueling the super drive segment of the tape market, including new demands for long-term data retention, the trend toward storage consolidation, increased use of automation, enhanced backup architectures such as disk-to-disk-to-tape, and continuing growth in network storage requirements.
In particular, the ongoing end-user trend toward consolidation and centralization of tape resources is driving end-user adoption of super drives.
For those keeping score, Hewlett-Packard moved into the leader position (28% market share in terms of revenue) in the overall compact tape market last year (based primarily on strong sales of its LTO drives), bumping Quantum (DLT/SDLT) into the runner-up position with a 27% market share. IBM (17%) came in third place, followed by Certance (13%) and Sony (10%). Three other vendors shared the remaining 5% of the market.
In the fast-growth super drive segment, Quantum retained the top position with a 33.5% market share, followed by Hewlett-Packard at 29%, IBM (24.8%), Sony (6.5%), Certance (5.4%), and Tandberg (0.8%) in terms of unit shipments.
SDLT vs. LTO
The most heated battle among tape formats is between Quantum's SDLT (which is also manufactured by Tandberg) and the LTO Ultrium format—which is supported by drive manufacturers Certance, Hewlett-Packard, and IBM—with Sony's SAIT format representing the dark horse.
Abraham predicts that shipments of DLT/SDLT will grow at a 12% annualized rate over the next six years, while LTO shipments are expected to grow at a 15% annual rate. Production shipments of Sony's SAIT drives, which are the capacity leaders at 500GB per cartridge, began early this year.
In terms of unit shipments of super drives, LTO captured a 59% market share last year, followed by SDLT at 34% and AIT/SAIT at 6.5% (see pie chart, p. 34). In terms of autoloaders for compact tape drives, 32% were based on LTO, 31% on DAT devices, and 25% on DLT/SDLT.
Abraham attributes LTO's success primarily to a time-to-market advantage. For example, LTO-2 drives began shipping in early 2003—with performance and capacity advantages over SDLT—while Quantum didn't ship its next-generation SDLT 600 drives until very late in 2003. As such, LTO had a banner year in 2003. However, Abraham notes that the tape drive market is a leapfrog contest in which one format enjoys technical superiority for an average of nine months and then another format takes the lead.
LTO-2, the latest generation of LTO drives, has a cartridge capacity of 200GB and a data-transfer rate of 35MBps, which is approximately equal to SDLT's 36MBps transfer rate. SAIT has a transfer rate of 30MBps.
High-end 8mm drives such as Sony's AIT-3 and, soon, AIT-4 (see "Sony readies AIT-4"), also compete with the super drive segment of tape drives.
Abraham says that next-generation LTO drives—LTO-3—might be available in limited quantities by year-end, although production shipments aren't expected until next year. LTO-3 will have a native capacity of 400GB (800GB assuming 2:1 compression) nd a native transfer rate of 80MBps (or 160MBps with 2:1 compression).
One of the more interesting trends in the tape market is a move by end users toward write-once capability (also referred to as write-once, read-many—or WORM), which is available with the AIT/SAIT, IBM 3592, and StorageTek 9840 formats. Abraham says that write-once capability may be available on SDLT and/or LTO drives by year-end.
Tape backup 1.01: Tips from the TTC
By Rich Harada
Designing a backup system that meets your company's requirements can be a challenge and involves an analysis of what technology to use, how often to back up, and where to store the data once it's backed up.
Here are some tips to keep in mind when you are planning your backup system:
Frequency—The best backup is the one that just completed before the system crashed. The longer the period between the last backup and a data loss event, the more data that will need to be re-created. However, the more often backups are performed, the more it will cost in tape media, lost productivity from system unavailability, and other storage management activities. It's important to note that a successful backup program requires regular evaluation and testing of the backup system to make sure it's working properly and that the stored data can be retrieved if necessary.
Retention—Very often, especially with virus and worm attacks, damage to files isn't recognized for some period of time, meaning that the last tape backup set may also contain the virus and/or corrupted data. That's why it's important to retain historical backup sets, so that the system can be brought back to a point in time before the data loss occurred.
Off-site vaulting—The removability of tape cartridges makes it easy to store them away from the primary storage. Always store your backup copies off-site at a location that is far enough away so a disaster won't strike both locations.
Full vs. incremental—A full tape backup provides the easiest method for data recovery, since all data is resident within the backup set. However, depending on the system architecture being used, full backups can have a highly detrimental impact on system availability. Incremental backups copy only the data that has changed since the last backup, greatly reducing the amount of time needed to perform the backup, but requiring more management of the recovery process.
Centralized vs. distributed—Corporations with multiple locations need to protect data generated at all sites. Some believe that capturing data close to its point of origin is best, while others say that centralizing backup operations provides tighter process control and higher success rates. Centralized backup operations are far less expensive overall.
The specific priorities and regulatory mandates of the organization should determine how each of the above variables is applied to the data-protection program. Many enterprises consider a 14-day rotating cycle, using three full tape backups and 12 incremental backups to be the best practice for cost-effective data protection. Starting with the full tape backup from the previous cycle:
- Days 1-6: Incremental tape backup
- Day 7: Full tape backup
- Days 8-13: Incremental tape backup
- Day 14: Full tape backup
- Following Day 14: Keep the tapes from the past seven days on-site, while rotating the previous 14 tapes to an off-site storage facility. A previous set of tapes should be returned from the vault to be re-used (to reduce media costs).
- Monthly: Full tape backup, sent to the off-site vault for long-term archival.
The timing and the processes used can be adjusted to suit the organization's data-protection goals.
Rich Harada is the president of the Tape Technology Council (www.tapecouncil.org). TTC members include Fujifilm, IBM, Imation, Maxell, Quantum, Sony, StorageTek, and TDK.
Compact tape vendors
Sony readies AIT-4
Sony last month announced the fourth generation of its AIT drives and media. Shipments are expected in either September or October.
Key specs for AIT-4 include the following:
- 200GB native capacity per cartridge (520GB assuming 2.6:1 compression);
- Native transfer rate of 24MBps;
- 3.5-inch form factor;
- Backward read/write compatibility with AIT-3 media, and read compatibility with AIT-2 and AIT-1 media;
- 8mm media with Advanced Metal Evaporate II technology and helical-scan recording;
- Remote-Memory-In-Cassette (R-MIC) technology, which speeds data access time; and
- Ultra160 SCSI interface (support for Serial ATA II is due in 2005).
From a technology standpoint, AIT-4 is classed in the high-end 8mm tape format category, but from a performance and capacity perspective AIT-4 also competes with "super drives" such as SDLT and LTO Ultrium.
Write-once, read-many (WORM) functionality will be included in AIT-4 late this year, according to Brett Schechter, senior manager of tape solutions at Sony. Previous generations of AIT drives/media already support WORM.
Autoloaders and low-end libraries supporting AIT-4 are also expected in the September or October time frame from Sony and its AIT library OEMs. (Sony's four largest AIT library OEMs are, in alphabetical order, ADIC, Overland Storage, Qualstar, and Spectra Logic.)
MSRP for an internal AIT-4 drive is expected to be slightly less than $3,500, with media pricing approximately $85 per cartridge, according to Schechter.