Storage media giant Imation will next year ship mid-range LTO tape cartridges with disk drives instead of tape inside, in order to provide very easy migration to disk-based backup.
Named Ulysses – presumably in honor of the creator of the wooden horse of Troy – the disk-powered cartridges will only run in special drives, but these drives will emulate or appear logically identical to SCSI tape drives. That will allow them to be inserted into a storage system with zero disruption to existing backup procedures.
Imation is describing the system as a tape accelerator, and says an entry-level configuration will cost between $5,000 and $10,000. The disk-cartridges are likely to cost a few hundred dollars each, and when first shipping in Q106 will feature 100GB drives. That is the currently the biggest capacity of rugged and portable ATA drives available, but Imation said later cartridges will be fitted with bigger disks. The tape-emulator drives will be forward-compatible.
At 32Mbytes per second, the throughput of the system will be the same as the maximum sustained by a conventional LTO-2 tape drive, so Ulysses will not necessarily speed the backup process itself. More importantly however, disk provides much faster data recovery because it allows random access to data. Imation said it had simulated the recovery of six files from a 20GB backup volume containing 100,000-odd files. From tape the recovery took 5.5 minutes, and from Ulysses it took 40 seconds, according to Imation.
Ulysses can also be used as a staging post for backups, in which data is first backed up onto a disk-powered cartridge, and later copied to tape. Imation said the disk-cartridges can be used with existing tape cloning and staging procedures. The disk-cartridges can withstand a fall from 30 inches onto a carpeted floor, which Imation said is the same standard as for LTO tape cartridges.
Ulike tape cartridges, the disk-powered cartridges will not be susceptible to the dreaded shoe-shining that can heavily cut tape drive throughput. Shoe-shining happens when data is fed to a tape drive slower than the drive is writing to tape, and sees the tape stopped, rewound and then nudged forward in order to find a re-start position. One way to prevent this is to multiplex or combine multiple backup streams, but this slows data recovery from tape by a factor of three or four, Imation said.