From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeremy Fitzhardinge Subject: Re: Greater than 16 xvd devices for blkfront Date: Thu, 08 May 2008 23:14:34 +0100 Message-ID: <48237B4A.4070808@goop.org> References: <48209705.4030005@redhat.com> <20080507015502.GA2121@redhat.com> <20080507034726.GC2121@redhat.com> <20080507164031.GB18143@sequoia.sous-sol.org> <18466.51240.492762.405781@mariner.uk.xensource.com> <20080508153350.GO17453@sequoia.sous-sol.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20080508153350.GO17453@sequoia.sous-sol.org> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Chris Wright Cc: "Daniel P. Berrange" , Chris Lalancette , Ian Jackson , xen-devel List-Id: xen-devel@lists.xenproject.org Chris Wright wrote: > Well, we don't actually need 202, or any minor numbers at all. The major > is only needed for the case where xvd masquerades as IDE or SCSI. > We ripped this wart out for upstream Linux. I'm considering putting it back in if it makes anyone's life easier. In general using labels/uuids is the best way to make an installation device-agnostic, but installers might have an easier time with a forged scsi device or something. I mentioned it in passing to Al Viro, and he was surprisingly non-insulting about the notion. > And the guest can happily > dynamically allocate minor numbers on its own behalf. A disk discovery > event can be completely dynamic, the admin just wouldn't be able to > guarantee which minor slot gets allocated for a particular disk in > a guest. We do have mount by label or UUID. > That's true for filesystems which have already been initialized. But if you're attaching 4 new devices to a guest and they appear at random device nodes, how do you know which is which? Smell? J