Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964884AbWHXPBQ (ORCPT ); Thu, 24 Aug 2006 11:01:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964946AbWHXPBP (ORCPT ); Thu, 24 Aug 2006 11:01:15 -0400 Received: from outpipe-village-512-1.bc.nu ([81.2.110.250]:51850 "EHLO lxorguk.ukuu.org.uk") by vger.kernel.org with ESMTP id S964884AbWHXPBP (ORCPT ); Thu, 24 Aug 2006 11:01:15 -0400 Subject: Re: Linux: Why software RAID? From: Alan Cox To: Marc Perkel Cc: Adam Kropelin , Jeff Garzik , Linux Kernel , Linux RAID Mailing List In-Reply-To: <44EDB843.2020608@perkel.com> References: <20060824090741.J30362@mail.kroptech.com> <1156425650.3007.140.camel@localhost.localdomain> <44EDB843.2020608@perkel.com> Content-Type: text/plain Content-Transfer-Encoding: 7bit Date: Thu, 24 Aug 2006 16:21:32 +0100 Message-Id: <1156432892.3007.155.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.6.2 (2.6.2-1.fc5.5) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 920 Lines: 18 Ar Iau, 2006-08-24 am 07:31 -0700, ysgrifennodd Marc Perkel: > So - the bottom line answer to my question is that unless you are > running raid 5 and you have a high powered raid card with cache and > battery backup that there is no significant speed increase to use > hardware raid. For raid 0 there is no advantage. > If your raid is entirely on PCI plug in cards and you are doing RAID1 there is a speed up using hardware assisted raid because of the PCI bus contention. If your controllers are PCI express, on internal high speed busses (eg chipset controllers) or at least half of them are then generally there is no win with hardware raid 0/1 and it is often slower. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/