Product Reviews

Most tape formats in the SMB backup market are in complete disarray, but Sony's AIT promises six generations and has delivered the first five on schedule. However, the format suffered a setback in 2005 as reports started coming in that using AIT-2 and AIT-3 tapes in the new AIT-4 drive caused serious problems, so Sony had to withdraw allbackward compatibility claims. It introduced the AIT-3Ex as a bridge to allow existing users of the lower-capacity AIT drive to migrate upwards, but this wasn't ideal. AIT-5 aims to set the record straight, as Sony claims full backward read and write compatibility with AIT-3, AIT-3Ex and AIT-4 media.

However, sacrifices have been made to keep to the product roadmap schedule. Although native capacity has increased to an impressive 400GB, Sony has kept native performance at 24MB/sec, the same as AIT-4. This isn't a major issue, as the drive offers the highest capacity for this form factor and performance is good enough to handle the demands of mid-range server backup.

Well aware of the problems surrounding AIT-4, we weren't prepared to take backward compatibility

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claims atface value, so decided to test to destruction. The internal drive on review was installed in a Supermicro dual 3GHz Xeon 5160 server running Windows Server 2003 along with Symantec's latest Backup Exec 11d (see p148). We used a 7.5GB mix of data representative of an average departmental server. Using Backup Exec's scheduling tools, we asked the drive to erase a tape, run a full backup, verify the contents and run each task again, and to keep doing it until 250passes for each process had been completed. We then ran a repeating job that restored the test data to a new location on the server, also for 250 passes. This four-phase process was run first with a single AIT-3 tape, then AIT-4 and finally on AIT-5. Overall, the test took around 500 hours and resulted in 1,000 passes for each media type.

On completion, Backup Exec reported zero failures on all three media types, so it looks like Sony has delivered on its compatibility claims. We also ran general performance tests for AIT-5 media across Backup Exec, CA's ARCserve 11.5 and EMC's Retrospect 7.5. ARCserve delivered the best results, with it returning 29MB/sec and 28.9MB/sec for backup and restore tasks respectively.

AIT now looks in a much stronger position than it did a year ago, and there are also question marks over many competing formats. HP's DAT160 is a year behind schedule, VXA is under the auspices of Tandberg Data after Exabyte put itself up for sale in 2006, and Quantum's DLT-V4 can only muster a 10MB/sec native transfer rate. With AIT-3 drives phased out in favour of AIT-3Ex, Sony now offers a solid migration path across five generations of AIT products and there's still a sixth to come.