Electrical, Duct, Scotch: The Answer Is Tape

By David A. Harvey  Assuring the data integrity of your workgroup means making intelligent choices about backup technologies. On one hand, you want the fastest and highest-capacity technology available. On the other hand, your bottom line dictates that the solution you deploy must be both cost-effective and reliable. The good news is that tape technologies fit the bill in every possible way. Thanks to seamless integration between backup software and tape drives, drives have become virtually indistinguishable from an installation and operation point of view. Nevertheless, numerous tape technologies exist for varying needs. Making the choice is simple: Factor in the amount of data and the size of your backup window. Large w orkgroups or workgroups with mission-critical databases that must be backed up quickly should implement DLT. For smaller groups, or those with wider backup windows, any of the 8-mm technologies are quite suitable. Take a slight step down on performance and capacity requirements, and DDS-3 DAT or MLR are the optimal solutions. In this workshop, we examine DAT, DLT, 8 mm and QIC and determine what fits your workgroup's environment and your budget. DAT (Digital Audio Tape) DAT is the station wagon of tape technologies. Stolidly economical, 4-mm DAT blends reliability, decent storage capacity and workhorse throughput to create a low- to mid-range offering. Despite several compatibility wars, DAT has remained backward-compatible and continues to grow in both capacity and transfer rate. The current standard for DAT is DDS (Digital Data Storage)--an HP and Sony collaboration--of which there are several varieties. Most important are today's DDS-3 and the soon-to-be released DDS-4. DDS-3 holds 12/24 GB (native/compressed) of data and is capable of transferring data at an acceptable rate of 1.2 MB per second--2.4 MB per second compressed. DDS-4 will double that capacity. We examined HP's SureStore DAT24, a DDS-3-compatible DAT with a SCSI-1 interface. We quickly learned that compression ratios were underwhelming. The problem, acknowledged by manufacturers, is the amount of precompressed files--.ZIP, .GIF, .JPG, .BMP--which greatly reduces the overall compression ratio. Ultimately, our overall compression ratios for four drives' worth of data ranged between 1.25:1 and 1.5:1. The DAT backups were reasonably quick. While they lagged behind the DLT, 8-mm and MLR drives, these backups were noticeably faster than the Travan TR-4 drive. You won't grimace when you get the bill for DAT. Average drives hit the street for about $2,000, with a piece of media coming in at about $40 and an operating cost (excluding the drive) of about $3.33 per gigabyte.