Re: Virtualization project idea

[Michal Novotny <minovotn@redhat.com>]

On 08/27/2010 03:33 PM, Pasi Kärkkäinen wrote:
> On Fri, Aug 27, 2010 at 03:26:46PM +0200, Michal Novotny wrote:
>    
>> On 08/27/2010 03:22 PM, Pasi Kärkkäinen wrote:
>>      
>>> On Fri, Aug 27, 2010 at 03:18:01PM +0200, Christoph Egger wrote:
>>>
>>>        
>>>> On Friday 27 August 2010 15:08:47 Pasi Kärkkäinen wrote:
>>>>
>>>>          
>>>>> On Fri, Aug 27, 2010 at 06:33:35PM +0530, Dhananjay Goel wrote:
>>>>>
>>>>>            
>>>>>>      Yes, exactly. So, we wanted to know if it is possible to *share USB*
>>>>>>      across VMs.
>>>>>>
>>>>>>              
>>>>> I don't think USB protocol has been designed for *sharing*.
>>>>> I'm pretty certain only one computer/device/VM can use USB device at a
>>>>> time.
>>>>>
>>>>>            
>>>> This might work with firewire devices, I'm not sure.
>>>>
>>>>
>>>>          
>>> 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
>>>
>>>
>>>        
>> 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?
>>
>>      
> 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 computers.
>
> People have implemented for example cheap proof-of-concept failover Oracle DB clusters
> using firewire disks as cheap 'shared storage'.. there are many tutorials
> about that on the internet.
>
> -- Pasi
>
>    
Oh, great! Thanks for sharing this information!

Michal

-- 
Michal Novotny<minovotn@redhat.com>, RHCE
Virtualization Team (xen userspace), Red Hat