I have 14 18Gig disks in a RAID5. When it re-builds I get just over 6Meg/sec. That's 6M per disk, or 84Meg total I/O per second. The CPU load is less than 5%. My system is a P3-500. If I had a real computer I would not be able to measure the CPU usage, it would be too low! :) I have a 2.4 Kernel. My SCSI buses are the limiting factor. 40MB bus with 6 disks, 80MB with 7, 80MB with 1. I have only used a few hardware RAID cards, they are not this fast! -----Original Message----- From: linux-raid-owner@vger.kernel.org [mailto:linux-raid-owner@vger.kernel.org] On Behalf Of Scott Long Sent: Thursday, February 19, 2004 5:34 PM To: Ricky Beam Cc: Michael; linux-raid@vger.kernel.org Subject: Re: 3ware escalade vs software raid, from a different jeff 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 - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
