The past couple of years has seen the entry level backup market thrown into turmoil with tape formats either being abandoned and then resurrected or taking a worrying amount of time to produce a new generation. However, in the midst of all this chaos one tape format has consistently delivered a cost-effective backup solution with a solid development programme going back over six years. Sony’s AIT (advanced intelligent tape) products combine all these elements along with excellent performance and capacity and the introduction of two new ATAPI versions makes a very tempting proposition for entry-level server and workstation backup duties. Sony has reduced the prices of its SCSI-based AIT-1 and AIT-2 drives to reposition them to compete with the DDS-3 and DDS-4 formats and the StorStation AIT90ai and AIT130ai drives make for an even stronger argument as they cost substantially less and yet deliver greater performance and capacity – even the original AIT-1 format is faster than HP’s new DAT72 drive. The drives employ the same helical scanning recording technology as DDS but use larger 8mm AME (advanced metal evaporated) tapes. Memory effect
AIT uses a feature of the tape cartridge called MIC (memory in cartridge) which consists of a 64Kbit flash memory chip mounted internally and accessed via a five-pin connector. MIC aims to reduce the time spent by the drive in searching for data as it stores information that is normally found on the first segments of the tape. This allows the drive to estimate how far to fast-forward or rewind the tape when searching for data and also unload it without having to rewind it first. Another key feature is that all AIT generations are backward read and write compatible with their predecessors so investment in media isn’t wasted. Testing showed that performance hasn’t been sacrificed as both drives deliver the same speeds and capacities as their SCSI counterparts. However, we did find that older IDE controllers can have a big impact on performance. With the drives installed on a server based around an older Intel STL2 motherboard equipped with a single primary IDE channel we saw backup speeds struggle to top 180MB/min. These problems evaporated with the drives installed in a Xeon-based server with the latest SuperMicro X5DP8-G2 board. Whilst securing 5GB of test data under Computer Associates ARCserve 9 and Veritas Backup Exec 9 we saw the AIT90ai return top backup and restore speeds of 266MB/min. The AIT130ai delivered equally impressive rates for backup on both software platforms with it averaging 392MB/min while a complete restoration returned over 390MB/min clearly showing both drives are more than capable of delivering the quoted native performance. The ATAPI interface has always been viewed as a poor choice for backup applications as historically it has been extremely slow with Seagate’s aging Travan drives a prime example. These two new drives from Sony dispel this myth as both perform extremely well and have the added bonus of comparatively high storage capacities making them the best alternative to DDS for entry level backup.