From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bill Davidsen Subject: Re: Linux: Why software RAID? Date: Mon, 04 Sep 2006 13:29:22 -0400 Message-ID: <44FC6272.9000403@tmr.com> References: <20060824090741.J30362@mail.kroptech.com> <1156425650.3007.140.camel@localhost.localdomain> <20060824093616.K30362@mail.kroptech.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Gordon Henderson Cc: Adam Kropelin , Linux RAID Mailing List List-Id: linux-raid.ids Gordon Henderson wrote: >On Thu, 24 Aug 2006, Adam Kropelin wrote: > > > >>>Generally speaking the channels on onboard ATA are independant with any >>>vaguely modern card. >>> >>> >>Ahh, I did not know that. Does this apply to master/slave connections on >>the same PATA cable as well? I know zero about PATA, but I assumed from >>the terminology that master and slave needed to cooperate rather closely. >> >> > >I don't know much about co-operation between master & slave, but I do know >that a failing PATA IDE drive can take out the other one on the same bus - >or in my case, render it unusable until I removed the dead drive, >whereupon (to my relief) it sprang back into life. > >This was many many moons ago before I started to use s/w RAID, but it's >one thing that would kill a multi-disk array, so I've never done it since. > >I guess the same could happen on SCSI, but I suspect the interface is a >little better designed... > Until recently I was working with 38 systems using SCSI RAID controllers (IBM ServeRAID Ultra320). With several types of SCSI drives I saw failures where one drive failed, hung the bus, and caused the next command to another drive to fail. At that point I have to force the controller to think the 2nd drive failed was okay, and then it would recover. I'm told this happens with other hardware, I just haven't personally seen it. From that standpoint, the SATA on the MB look pretty good! -- bill davidsen CTO TMR Associates, Inc Doing interesting things with small computers since 1979