Re: Write-up on RAID
Joe Lumbley in Dallas writes: >Please clarify for me in this forum: >1. What ***exactly*** is RAID level 7? >2. Does anyone **else** use the term "RAID 7" or is this just > a buzzword that you guys have dreamed up to mean RAID 5 with > a RAM-Disk? > postings....arouse interest as a performance tuner... Hi Joe, Storage Computer first had an operating RAID 3 running back in 1984, three years before the Berkeley RAID papers were published, then a RAID 4 and a 5. Finding these architectures to be fundamentally flawed regarding performance versus a single spindle disk, the company continued RAID theory and engineering work since then, finally coming out with RAID 7 a couple of years ago. RAID 7s are now installed in over 600 major, well-known customer sites worldwide, operating in mission-critical applications. (For example, there is a new customer reference story in the January 1995 Unisys World issue.) We have a number of technical whitepapers describing how RAID 7 I/O-acceleration works, and how the performance multiples are achieved. We don't disclose all the technical details of how this works for competitive reasons. No other vendor has yet figured out exactly how RAID 7 works, although I do understand that there has been one vendor shipping a RAID product across state lines, claiming it was a RAID 7. In general, RAID 7 performance increase multiples over the earlier RAID levels are achieved through a special real time operating system with unique memory management algorithms, unique parity overhead minimization processes, a high performance built-in CPU, parallel processing with a dedicated processor on each disk channel, multiple layers of high speed cache, and a no-wait architecture allowing immediate processing of reads and writes versus typical RAID synchronous architectures (with lots of wait time). We prove the performance increases to customers at their sites with their hardware, their OSs, their particular patches, their particular applications, and their particular user loads. Our customers typically insist on this sort of proof, rather than canned benchmark results provided by vendors. Regarding proof in Texas, you can take a look at RAID 7s at the February 13-17 Government Technology Conference in Austin. Storage Computer will be demonstrating RAID 7 interoperability with HP/DEC/SGI/Sun/etc. hardware at booth 216 at the Austin Convention Center (exhibit is Feb. 15-17). (A single RAID 7 can serve up to 12 different vendor hosts simultaneously). Storage Computer will be next to the HP booth. Information about the show is available by calling 916-363-5000. Information about Storage Computer participation is available by calling SCC terabyte program director Eileen Chalifoux at 603-880-3005 (SC7TByte@World.std.com) or regional vp Barry Winans at 404-926-4699 (ATLSCC@aol.com). Michael Willett, EE Storage Computer Corp. 11 Riverside Street Nashua, NH 03062 Tel. 603-880-3005 :::I/O-accelerated, very fast disk arrays for all SCSI systems to 1,000 GB::: :::::::::::::::::::::::::::We make SCSI systems scream.::::::::::::::::::::::