From mboxrd@z Thu Jan 1 00:00:00 1970 From: Al Boldi Subject: Re: [PATCH md 006 of 6] Add write-behind support for md/raid1 Date: Sat, 13 Aug 2005 08:00:32 +0300 Message-ID: <200508130800.32901.a1426z@gawab.com> References: <20050811171720.10115.patches@notabene> <200508120922.52689.a1426z@gawab.com> <42FC92C6.7060604@steeleye.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <42FC92C6.7060604@steeleye.com> Content-Disposition: inline Sender: linux-raid-owner@vger.kernel.org To: Paul Clements Cc: NeilBrown , Andrew Morton , linux-raid@vger.kernel.org List-Id: linux-raid.ids Paul Clements wrote: > Al Boldi wrote: > > NeilBrown wrote: > >>If a device is flagged 'WriteMostly' and the array has a bitmap, > >>and the bitmap superblock indicates that write_behind is allowed, > >>then write_behind is enabled for WriteMostly devices. > > > > Nice, but why is it dependent on WriteMostly? > > WriteMostly is just a flag that tells us which devices will get the > write-behinds, and which will not. You'll be able to mix any > combination of WriteMostly devices and normal devices in a raid1. > Yes, but doesn't WriteMostly imply ReadDelay? If so, doesn't that mean that WriteBehind is dependent on ReadDelay? -- Al