From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eero Volotinen Subject: Re: mptsas and mptbase sas problems on fujitsu-siemens rx200-s3 rack server Date: Fri, 22 Aug 2008 17:46:20 +0300 Message-ID: <48AED13C.7080106@iki.fi> References: <48AE9DFB.7070502@iki.fi> <1219414589.3339.8.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from pokat.org ([193.208.0.238]:39484 "EHLO pokat.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752101AbYHVOrS (ORCPT ); Fri, 22 Aug 2008 10:47:18 -0400 In-Reply-To: <1219414589.3339.8.camel@localhost.localdomain> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: James Bottomley Cc: linux-scsi@vger.kernel.org > The first thing to note is that HBA based hardware RAID is not something > anyone should enable blindly. The fusion isn't even a dedicated RAID > card, so its RAID engine is effectively jammed into left over firmware > space because it was available (HP, for instance, required this > capability to be removed on some of the HP OEM models). > > Even for dedicated hardware RAID, the problem you have is that it > effectively puts the onboard processor in the direct I/O path. Since > cards are (reasonably) cheap, these processors don't have the fastest > busses or highest processing capabilities, and often top out at > surprisingly low bandwidths, especially for compute intensive > transactions like RAID-5/RAID-6. Mainly this internal sas array (2*73GB 10k sas disks) is used for operating system only. Currently I am running it on raid1 After weekend I can try to run it without hardware acceleration, it mainly makes installing operating system a bit harder. So, this looks like that I need to buy working sas raid controller, if I want to use hardware raid on this machine? Rest of data is on fibrechannel san and it is working fine. -- Eero