From mboxrd@z Thu Jan 1 00:00:00 1970 From: malahal@us.ibm.com Subject: Re: [RFC][PATCH 0/4] dm-log: support multi-log devices Date: Mon, 5 Jan 2009 08:24:35 -0800 Message-ID: <20090105162435.GB18452@us.ibm.com> References: <492C91DF.7040507@redhat.com> <49467039.6060801@redhat.com> <20081220001305.GA8574@us.ibm.com> <49502F7E.9040300@redhat.com> <20081223180228.GA24831@us.ibm.com> <49622ADB.7040200@redhat.com> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <49622ADB.7040200@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: Takahiro Yasui Cc: dm-devel@redhat.com, agk@redhat.com List-Id: dm-devel.ids Takahiro Yasui [tyasui@redhat.com] wrote: > Hi Malahal, > > my patch doesn't handle transient error now. I expect log devices > to be failed and got in a blockage status once an error has happened. > > > With our user level only implementation, the log device handling would > > be as good as the real mirror *leg* handling. We get all the benefits of > > the mirror without doing any code! Wouldn't it be nice? > > I agree that simple implementation is better, but log could be handled > without any additional layer, and also I'm thinking that log could be > handled in the simpler way. > > Lower layer, such as SCSI, also has retry feature based on error type > and will be done in the proper way. Do you mean that it isn't enough > and should dm-layer handle errors for log device, too? Not really. What I meant is re-integrating a failed log device when it comes back again. That is also what I mean by handling 'transient errors'.