Certance CL-800 Desktop review

Over the past three years, Enterprise has brought you exclusive first looks at every new small business and mid-range tape backup format. This month, we do it again with the very latest Ultrium LTO-3. No other format has had such an impact on the mid-range backup market and this third generation steps up the pace even more. It delivers an impressive native transfer rate of 68MB/sec and massive storage capacity of 400GB on solid 0.5in cartridges.

Normally the least aggressive of the three LTO consortium members, Certance takes a commanding lead over IBM and HP, with the latter advising us that it isn't planning to release an LTO-3 drive until early 2005. Modifications made to improve performance and capacity comprise a tape length increase to 650m, a recording density up to 704 tracks and 245Kb per inch, and a doubling of the internal buffer to 128MB.

A set of open standards form the foundation of LTO and all products must pass an independent compliance verification program. However, that hasn't stopped each vendor adding their own little touches and Certance includes its MediaShield, SmartVerify, Dynamic Powerdown and 13-Speed Transfer technologies. MediaShield is simply a set of tape path design criteria that aims to cut media stress by reducing contact with the rollers and head. SmartVerify provides four stages of ECC where data is checked as it goes across the SCSI bus, into and out of the buffer and through the compression engine. Dynamic Powerdown aims to physically protect the tape as the drive maintains a small amount of stored power that is used to gently slow the supply and take-up reels to a full stop in the event of a power failure. Certance claims its 13-Speed Transfer is unique, but it's not actually that different to HP's ATS (adaptive tape speed) technology, which is also designed to match the speed of the drive with the host to improve streaming.

To test real-world performance we used a Dell PowerEdge 2850 rack server (see p186) running Windows Server 2003. We connected the CL-800 to a dedicated Adaptec Ultra320 PCI card. Backup software came courtesy of Computer Associates ARCserve 11 and Veritas Backup Exec 9.1 and we used a 9GB mixture of test data comprising a wide variety of compressible and uncompressible files. ARCserve delivered marginally better overall speeds, with it returning 48MB/sec and 47MB/sec for backup and verification respectively, while a full restoration was completed at an average of 37MB/sec. These are impressive speeds but note that the CL-800 failed to reach its quoted native transfer rate. We did run another backup with 500MB of highly compressible files, which returned a storming 79MB/sec, but these speeds are unlikely to be achieved in the real world.

The CL-800 confirms LTO's dominance in the mid-range backup market, and this third generation delivers on the capacity promises made in the roadmap. It easily outperforms SDLT600, although it's worth noting that WORM support is still on the drawing board. Strangely, throughout all our real-world tests on LTO the Certance implementations have tended to underperform, and we see this again with the CL-800 failing to make the quoted speeds. Certance certainly delivers an impressive range of features at a competitive price, but if performance is your key requirement then you may want to wait for HP and IBM to launch their respective LTO-3 products.

Author: Dave Mitchell