Date: Sat, 27 Oct 2001 10:22:14 +0930 From: Greg Lehey <grog@FreeBSD.org> To: Matthew Jacob <mjacob@feral.com> Cc: Doug Rabson <dfr@nlsystems.com>, Luigi Rizzo <rizzo@aciri.org>, John Baldwin <jhb@FreeBSD.org>, Jonathan Lemon <jlemon@FreeBSD.org>, cvs-all@FreeBSD.org, cvs-committers@FreeBSD.org Subject: RAID-5 parity calculations (was: cvs commit: src/sys/dev/fxp if_fx) Message-ID: <20011027102214.C7091@wantadilla.lemis.com> In-Reply-To: <Pine.BSF.4.21.0110251520431.99888-100000@beppo>; from mjacob@feral.com on Thu, Oct 25, 2001 at 03:24:06PM -0700 References: <20011025231245.K549-100000@salmon.nlsystems.com> <Pine.BSF.4.21.0110251520431.99888-100000@beppo>
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On Thursday, 25 October 2001 at 15:24:06 -0700, Matt Jacob wrote: > > And the fastest software RAID-V I've known was at NASA/Ames on the > Convex 3280s- they used the otherwise unused vector units for parity > calculations- this gave write performance for a 22 wide stripe on a > terabyte fileystem to be at about 88% of theoretical maximum, which > sure aint' bad. The parity calculations for RAID-5 are several orders of magnitude faster than the disk accesses. Even on a 486, they took hardly any time. Greg -- See complete headers for address and phone numbers To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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