This article is from the storage FAQ part1, by Rodney D. Van Meter with numerous contributions by others.
(6/93) There are several tape array products on the market: Data General is selling the CLARiiON Tape Array Subsystem comprising between five and seven 4mm DAT tape drives. Data can be recorded in RAID-like striping redundancy, mirrored, or in conventional DAT layout. This unit can provide up to 30GB of unattended contiguous storage. The tape drives can record at sustained rates of 183 - 732 KB/second each but customers should expect sustained backup at around 1 megabyte/second of compressed data after accounting for host overheads. Data General is working on a seven tape caddie to hold tape sets together. It is essential that tapes in a RAID group not be separated. NCR announced a tape array software product for NCR uniprocessors and System 3450, System 3550 and StarServer Systems running UNIX V R4.2.01. This tape array software yields faster and more reliable backup of large database and file servers than with any single tape drive available today but uses customers existing tape devices. It writes simultaneously to multiple drives and can use array techniques to recover from loss or failure in any single tape. The motivations for tape arrays seems to parallel those for disk arrays: - higher bandwidths - increased reliability (firstname.lastname@example.org, Dick Wilmot, Editor, Independent RAID Report) (6/93) Pick up any DEC related trade rags and you can find an ad for an 8mm tape array. The ad I just found is by Contemporary Cybernetics and uses two five GB 8mm drives with compression - they CLAIM to be able to get 50 GB os storage total - but how many customers have 50 GB worth of 5:1 compressible data? Anyway - the ad doesn't mention RAID, but they support RAIDish (!) features such as striping and mirroring. It also supports offline tape-to-tape copy and will automatically cascade onto the second tape when the first one fills (useful for utilities that can't deal with multi-drive/multi- volume). I SEEM to remember someone having something like this with more drives, but of course I couldn't locate the ad. I would be really interested in seeing something like this for 3480 since the transfer rate is already quite high... (email@example.com, Tom Bodoh) At the Monterey IEEE Mass Storage Conference in April '93, Ann Drapeau from Randy Katz's group presented a paper on striped tape. The National Storage Lab High Performance Storage System reportedly supports striping of removable media in the system software. (rdv,95/1/13) Something that came through the newsgroup recently (95/2/5): Tape Arrays High Performance tape drive units for large networks and minis. Fast: up to 4Megabyes/second High Capacity: from 24Gb on 4mm DATS to 60GB on DLTs; with autoloaders,up to 616GB Flexibility: Stripe data across 4 drives, mirror data, stripe 2/mirror 2 - double your speed while creating an off-site storage copy; off-line copy; pass-thru mode, etc. Transparent to your backup software - no changes or retraining Compatible with all major OSs; including Novell, WindowsNT, Unix, Sun, HP, Silicon Graphics, VMS, etc. For More information: William Wirth Travlnmn@ix.net.com Just spotted this in a PC rag. Andataco can stripe, mirror or RAID DLT, 8mm or 4mm. Check out http://www.andataco.com or call 800-334-9191 or +1-619-453-9191. Or email firstname.lastname@example.org. (Andataco is an integrator for numerous storage products including RAID arrays.) Compaq now has a DLT tape array. Some specs available at http://www.compaq.com. Stripes or does RAID 5. (rdv, 96/4/17) Tecmar makes a tape array with up to 30 (custom) drives. A "rotating" spare is used to gradually back up the entire system. (Georg Feil, http://www.sgl.ists.ca/~georg, email@example.com, 96/10/17)