Despite its age, tape remains a mainstay of enterprise backup. Innovations in tape technology over the years have boosted performance and reliability while driving down price, preserving tapes place in the server room as a dependable backup medium.
Despite its age, tape remains a mainstay of enterprise backup. Innovations in tape technology over the years have boosted performance and reliability while driving down price, preserving tapes place in the server room as a dependable back–up medium.
Sony is hoping to reclaim market share lost in recent years to LTO (Linear Tape-Open) and SDLT (super digital linear tape) with its latest AIT (Advanced Intelligent Tape) drive. The drive, which began shipping in late 2006, is the first 8-millimeter- form-factor device to offer 400GB native capacity. With compression, overall capacity stretches to more than 1TB. Sony officials claim a native transfer rate of 24MB per second over the drives Ultra 160 SCSI LVD/SE interface.
The new AIT-5 features the same compact 3.5-inch, half-height form factor as its predecessor, the AIT-4, but with expanded backward read/write compatibility—spanning three generations, to AIT-3, AIT-3Ex and AIT-4 media. The AIT-5 also supports both regular and WORM media, making it suitable for compliance and auditing requirements.
eWEEK Labs tested an external AIT-5 drive model (AIT-e1040SLE) attached to a Dell PowerEdge 2800 server outfitted with two Intel Xeon processors and 2GB of RAM. Using Symantecs Backup Exec 11d for Windows Server (included with the drive and media in a limited-edition bundle), we tested backup performance under worst-case-scenario conditions, with 30GB of uncompressible data comprising .zip, MP3 and Divx movie files. Most environments deal with some combination of compressible and uncompressible data, so the results from this type of test serve as a base line for expected performance under less-than-ideal conditions.
At 23.3MB per second, the AIT-5s backup performance came fairly close to Sonys advertised 24MB-per-second native transfer rate, although both SDLT and LTO3 offer higher transfer speeds: Quantums SDLT 600 tabletop drive boasts 36MB-per-second native transfer performance, while Hewlett-Packards LTO3-based StorageWorks Ultrium 920 unit can more than double that rate.
Sonys AIT-5 still manages to store a bit more compressed data on each tape than its rivals, due to the higher 2.6-1 compression ratio of the ALDC (Adaptive Lossless Data Compression) algorithm it uses. In comparison, LTO and SDLT use the 2-1 compression provided by the DLZ (Digital Lempel Ziv) algorithm.
The AIT-5 also is rated at 400,000 hours MTBF (mean time between failure) versus just 250,000 hours for LTO3 and SDLT. To achieve this longevity, Sony uses helical- scan and low-friction AME (Advanced Metal Evaporation) III technologies. The former allows the drive to write to the entire media in a single pass, reducing the required number of passes needed; the latter helps the tapes withstand more error-free passes overall.
At $3,320 for the Limited Edition SCSI External model, the AIT-5 is priced competitively with external LTO3 and SDLT drives. Although the tape-format race has favored LTO3 in recent years, organizations seeking longevity and per-tape capacity over raw read/write performance may find the AIT-5 solution worth a second look. After all, reliability, capacity and economy wont take a back seat to performance in the realm of tape backup.
Technical Analyst Victor Loh can be reached at [email protected].
HPs StorageWorks Ultrium 920 HPs external SCSI tape drive, based on LTO3 technology, stores as much as 400GB native capacity tapes in a 3U (5.25-inch) half-height form factor over either an Ultra 320 SCSI LVD or 3GB-per-second SAS interface; native performance reaches up to 60MB per second (www.hp.com)
Quantums SDLT 600 Tabletop Drive This 300GB native/600GB compressed SCSI tabletop drive boasts 36MB-per-second performance over an Ultra 160 SCSI or 2GB Fibre Channel (for enterprise libraries) interface (www.quantum.com)
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