From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ming Zhang Subject: Re: Controlling Reading and Writing in RAID 1 configuration Date: Thu, 27 Apr 2006 21:31:52 -0400 Message-ID: <1146187912.11547.211.camel@localhost.localdomain> References: <20060425125814.6366.qmail@web52907.mail.yahoo.com> <17489.16385.884347.871210@cse.unsw.edu.au> <1146177496.11547.147.camel@localhost.localdomain> <17489.20083.873352.723996@cse.unsw.edu.au> Reply-To: mingz@ele.uri.edu Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <17489.20083.873352.723996@cse.unsw.edu.au> Sender: linux-raid-owner@vger.kernel.org To: Neil Brown Cc: Rik Herrin , linux-raid@vger.kernel.org List-Id: linux-raid.ids On Fri, 2006-04-28 at 09:06 +1000, Neil Brown wrote: > On Thursday April 27, mingz@ele.uri.edu wrote: > > > > On Fri, 2006-04-28 at 08:04 +1000, Neil Brown wrote: > > > On Tuesday April 25, rikherrin@yahoo.com wrote: > > > > Hi, > > > > I have a setup where I want to use RAID 1 to mirror > > > > my data over the LAN. I am exposing 2x500 GB-sized > > > > devices via iSCSI and was wondering if I could > > > > configure the RAID 1 to write to both members of the > > > > RAID 1 configuration but only read from one as one > > > > only read from one disk, shall this be a "--read-preferred" ? > > No. The one(s) you don't read from is the odd-one-out. The one(s) > you read from are 'normal' and don't get a special flag. > > > > > i checked email archive, but still not quite understand on this > > "--write-mostly". for raid1, u anyway need to write all components, so > > why there is a "mostly"? > > > > Mostly it will just write to this device. > But if all the non-write-mostly device fail, then it will read from > this device. So it isn't write-only. It is write-mostly. > > Make sense? i know why my English language test had that low score now. thx! > > NeilBrown