HP StorageWorks DAT 160

It's remarkable that it's taken over three years for the successor to DAT 72 to materialise, but DAT 160 has arrived and, in this exclusive review, we find out whether the wait has been worthwhile.

When it resurrected the DDS format early in 2003, HP was faced with a number of problems, as the 4mm cartridges were almost at their physical limits. HP needed to be able to pack more tape into the shell, so it had to make the substrate thinner to increase capacity from a native 20GB to 36GB. The biggest disappointment was that DAT 72 didn't increase performance over DDS-4, where it remained at 3MB/sec, making it one of the slowest backup formats around.

The DAT 160 was due to be launched in 2006, but was delayed for one reason. At the time, it was rumoured that the new drive would move from 4mm to 8mm media, and this is indeed true. However, to maintain backward compatibility HP wanted to ensure the drive could read and write to DAT 72and DDS-4 cartridges, so it designed a dual-loading mechanism -and this was the cause of the delay.

The thicker cartridges allow an increase in capacity to a native 80GB and performance goes up to 6.5MB/sec. At present, HP offers the drive as internal and external SCSI and USB 2 models, but you can expect a SAS version later this year. However, considering the target market is likely to be using entry-level servers, it would have made more sense for HP to offer a SATA version, too.

Both the USB and SCSI versions offer the same performance characteristics, and we tested the former with it attached to a Supermicro 3.2GHz Pentium D workstation running Windows XP SP2. For backup software, we used EMC's Retrospect 7.5 and the bundled Data Protector Express, which is identical to the Yosemite Backup 8.1 (web ID: 110718). With the former in control, we asked it to back up, verify and restore 13GB of data, with it reporting 5.6MB/sec, 6.4MB/sec and 6.3MB/sec respectively. Data Protector Express proved to be slightly faster, returning 6.4MB/sec, 6.3MB/sec and 6.5MB/sec for the same three tasks. We also used a DAT 72 cartridge to test for compatibility, and saw both backup products reporting a shade over 3MB/sec for backup and restoration tasks.

When the demise of DDS was announced in 2001, it came as no surprise to see HP resurrecting it in 2003. Furthermore, despite strong competition from formats such as Sony's AIT, low-end tape backup continues to be dominated by DAT and, according to a report by IDC, actually increased its market share in 2006.

The DAT 160 may have moved to an 8mm format, but backward compatibility ensures it offers a solid migration path to existing users of DAT 72 and DDS-4 tape drives. Performance is up to HP's claims, and another advantage of the wider media is that it's given HP room to move with its latest product roadmap, showing there's plenty more to come yet.

Author: Dave Mitchell