From mboxrd@z Thu Jan 1 00:00:00 1970 From: Scott Long Subject: Re: 3ware escalade vs software raid, from a different jeff Date: Thu, 19 Feb 2004 15:33:59 -0700 Sender: linux-raid-owner@vger.kernel.org Message-ID: <403539D7.30202@adaptec.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: To: Ricky Beam Cc: Michael , linux-raid@vger.kernel.org List-Id: linux-raid.ids Ricky Beam wrote: > On Thu, 19 Feb 2004, Michael wrote: > >Bear in mind that what you are calling "true hardware raid" is really > >a microprocessor programmed to do the raid algorithims. > > 3ware has custom designed matrix switch chips to handle each IDE drive. > This *alone* is worth the cost of the card. The RAID parity calculations > are also done in hardware (not a bunch of CPU xor's.) You'd be > surprised how > much data a small "slow" processor can move when properly programmed. > Are you talking about host-processor XOR or adapter card XOR? The i960 processor used in practically every RAID card known to man right now has an XOR engine in the memory controller. It's not quite as efficient as some higher-end implementations, but it's a heck of a lot better than having that i960 core spin through an XOR software loop. Scott