From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michal Novotny Subject: Re: Virtualization project idea Date: Fri, 27 Aug 2010 15:48:11 +0200 Message-ID: <4C77C21B.6070008@redhat.com> References: <20100827084622.GA2804@reaktio.net> <20100827130847.GG2804@reaktio.net> <201008271518.01980.Christoph.Egger@amd.com> <20100827132223.GH2804@reaktio.net> <4C77BD16.2030900@redhat.com> <20100827133333.GJ2804@reaktio.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20100827133333.GJ2804@reaktio.net> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: =?ISO-8859-1?Q?Pasi_K=E4rkk=E4inen?= Cc: Christoph Egger , xen-devel@lists.xensource.com, Dhananjay Goel , James Harper List-Id: xen-devel@lists.xenproject.org On 08/27/2010 03:33 PM, Pasi K=E4rkk=E4inen wrote: > On Fri, Aug 27, 2010 at 03:26:46PM +0200, Michal Novotny wrote: > =20 >> On 08/27/2010 03:22 PM, Pasi K=E4rkk=E4inen wrote: >> =20 >>> On Fri, Aug 27, 2010 at 03:18:01PM +0200, Christoph Egger wrote: >>> >>> =20 >>>> On Friday 27 August 2010 15:08:47 Pasi K=E4rkk=E4inen wrote: >>>> >>>> =20 >>>>> On Fri, Aug 27, 2010 at 06:33:35PM +0530, Dhananjay Goel wrote: >>>>> >>>>> =20 >>>>>> Yes, exactly. So, we wanted to know if it is possible to *sha= re USB* >>>>>> across VMs. >>>>>> >>>>>> =20 >>>>> I don't think USB protocol has been designed for *sharing*. >>>>> I'm pretty certain only one computer/device/VM can use USB device a= t a >>>>> time. >>>>> >>>>> =20 >>>> This might work with firewire devices, I'm not sure. >>>> >>>> >>>> =20 >>> Yeah, firewire (iee1394) is designed to so that you can attach >>> the devices to multiple computers.. >>> >>> If you attach the same firewire-disk to multiple computers, >>> and use the disk from multiple computers at the same time, >>> you *will* corrupt the filesystem on the disk. >>> >>> Unless you run some kind of filesystem that has lock-manager, >>> that can coordinate the shared access to the disk.. >>> ie. you must be running cluster-aware filesystem. >>> >>> -- Pasi >>> >>> >>> =20 >> Well guys, but we're talking about USB. The USB protocol is different >> from firewire one. But that's right that I didn't know that. How is it >> exactly done with the firewire to connect to multiple computers? >> >> =20 > Some (or all?) firewire devices have 'daisy chain' connectors, > so you can link multiple devices together.. > > You can use those connectors to hook up the same device to multiple com= puters. > > People have implemented for example cheap proof-of-concept failover Ora= cle DB clusters > using firewire disks as cheap 'shared storage'.. there are many tutoria= ls > about that on the internet. > > -- Pasi > > =20 Oh, great! Thanks for sharing this information! Michal --=20 Michal Novotny, RHCE Virtualization Team (xen userspace), Red Hat