From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alan Cox Subject: Re: Linux SATA RAID FAQ Date: Sat, 14 Aug 2004 16:21:53 +0100 Sender: linux-ide-owner@vger.kernel.org Message-ID: <1092496912.27156.6.camel@localhost.localdomain> References: <411B0F45.8070500@pobox.com> <20040812113413.GA19252@alpha.home.local> <411D5D70.9070909@clanhk.org> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from the-village.bc.nu ([81.2.110.252]:15323 "EHLO localhost.localdomain") by vger.kernel.org with ESMTP id S263775AbUHNQYQ (ORCPT ); Sat, 14 Aug 2004 12:24:16 -0400 In-Reply-To: <411D5D70.9070909@clanhk.org> List-Id: linux-ide@vger.kernel.org To: "J. Ryan Earl" Cc: Willy Tarreau , Jeff Garzik , Linux Kernel Mailing List , "linux-ide@vger.kernel.org" On Sad, 2004-08-14 at 01:31, J. Ryan Earl wrote: > On the brightside, md raid5 is often faster than hardware raid5. At > least on the 7000 and 8000 series of 3ware hardware; the 9000 series > looks promising though. I haven't seen megaraid SATA numbers, and I > don't know what happened to the SX8. Be cautious what you measure. One of he problems until you reach PCI-X is PCI bandwidth. Thus software md5 can look good but the moment its combined with other PCI activity goes down the pan entirely. > When the libata Marvell drivers come out, you'll have a cheap upgrade > path for PCI-X boards if you want fast md raid: Agreed. PCI-X will change a lot of this for boxes that are not very cpu/memory limited.