On Fri, Aug 27, 2010 at 04:56:33PM +0530, Dhananjay Goel wrote:
> Also you wouldn't see the changes made in other VMs,
> unless you made sure all the caches are refreshed etc in the VM all the
> time.
>
> You'd need to use some cluster-filesystem (GFS, GFS2, OCFS2, GPFS, etc).
> --Can you please suggest how NFS manages this because this case is handled
> by NFS without any corruption?
> We can share flash drive across VMs as we do with physical machines in
> LAN. Please help!
>
How are you sharing USB flash drives with physical machines?
-- Pasi
> Thanks,
> Dhananjay
>
> On Fri, Aug 27, 2010 at 4:27 PM, Pasi Kärkkäinen <[1]pasik@xxxxxx> wrote:
>
> On Fri, Aug 27, 2010 at 02:53:54PM +0530, Dhananjay Goel wrote:
> > This won't be straight forward. Think about USB memory/flash stick.
> > If every VM sees it, and simultaneously writes to it, the
> filesystem
> > in it will get corrupted immediately!
> >
> > --Why would it get corrupted immediately. Might be we can just lock
> a
> > specific file which is being edited? Please suggest.
> >
>
> Because USB level has no idea about filesystems or files, or locking
> them!
>
> Say you're using ext3 or NTFS in the VM for the USB device.
> Those filesystems are NOT cluster-aware, ie. they're not aware of any
> sharing,
> and they don't support any kind of sharing.
>
> They expect exclusive access to the device.
>
> If suddenly the bits on the device change from outside,
> the filesystem gets corrupted very easily.
>
> Also you wouldn't see the changes made in other VMs,
> unless you made sure all the caches are refreshed etc in the VM all the
> time.
>
> You'd need to use some cluster-filesystem (GFS, GFS2, OCFS2, GPFS, etc).
>
> -- Pasi
>
> > Thanks,
> > Dhananjay
> >
> > On Fri, Aug 27, 2010 at 2:49 PM, Pasi Kärkkäinen
> <[1][2]pasik@xxxxxx> wrote:
> >
> > On Fri, Aug 27, 2010 at 02:45:12PM +0530, Dhananjay Goel wrote:
> > > No, that's not possible with pvusb. pvusb is for direct
> passthru to
> > > one/single vm.
> > > You'd need some filesystem share (cifs/nfs/whatnot) to make
> such
> > sharing
> > > possible.
> > > Comments: Is it possible to share USB keyboard, USB mouse,
> USB
> > modem, etc
> > > across VMs i.e host and guest(s)? If we connect USB
> keyboard, is it
> > > possible to use it in guests?
> > >
> >
> > This is implemented in XCI (Xen Client Initiative), and there has
> been
> > some discussions how to get it traditional Xen, to help Xen VGA
> > Passthrough usage.
> >
> > See: [2][3]http://wiki.xensource.com/xenwiki/XenVGAPassthrough
> > > Also, is it possible for us to modify the device driver of
> USB 2.0
> > so that
> > > all USB 2.0 devices are visible and can be used across all
> VMs?
> > Please
> > > suggest.
> > >
> >
> > This won't be straight forward. Think about USB memory/flash
> stick.
> > If every VM sees it, and simultaneously writes to it, the
> filesystem
> > in it will get corrupted immediately!
> >
> > USB Passthru cannot be used to 'share' devices, it's for giving
> > one/single VM
> > direct access to the device.
> >
> > -- Pasi
> >
> > > Thanks,
> > > Dhananjay
> > >
> > > On Fri, Aug 27, 2010 at 2:16 PM, Pasi Kärkkäinen
> > <[1][3][4]pasik@xxxxxx> wrote:
> > >
> > > On Fri, Aug 27, 2010 at 01:37:49PM +0530, Dhananjay Goel
> wrote:
> > > > Hi James/Pasi,
> > > > I had a look at
> > >
> [1][2][4][5]http://wiki.xensource.com/xenwiki/XenUSBPassthrough
> > > > But I'm not sure if it supports sharing USB devices
> across
> > VMs
> > > (host and
> > > > guest) i.e. if I plug in a flash drive then it would
> detect
> > in both
> > > host
> > > > and guest and I'd be able edit files from all VMs
> rather
> > than
> > > mounting and
> > > > unmounting everytime from 1 VM to other.
> > > > Please let me know your thoughts on it.
> > > >
> > >
> > > No, that's not possible with pvusb. pvusb is for direct
> passthru
> > to
> > > one/single vm.
> > > You'd need some filesystem share (cifs/nfs/whatnot) to
> make such
> > sharing
> > > possible.
> > >
> > > -- Pasi
> > > > Thanks,
> > > > Dhananjay
> > > >
> > > > On Fri, Aug 27, 2010 at 4:28 AM, James Harper
> > > > <[2][3][5][6]james.harper@xxxxxxxxxxxxxxxx> wrote:
> > > >
> > > > > Hi there!
> > > > >
> > > > > First I'd like to say that XEN plaform is really
> cool
> > and
> > > awesome.
> > > > >
> > > > > I'm an engineering student and is searching for a
> > feasible
> > > project in
> > > > > virtualization. I'd like to know if its possible
> to
> > share USB
> > > devices
> > > > (flash
> > > > > drive, hard disk, mouse, keyboards etc) across
> guests
> > and host
> > > (VMs).
> > > > Also, do
> > > > > you have any idea to extend it? Or any innovative
> idea
> > so that
> > > we can
> > > > > implement it.
> > > > >
> > > > > I'd appreciate any help. Thanks in advance.
> > > > >
> > > >
> > > > Further to what Pasi said, I have partially ported
> the
> > backend
> > > interface
> > > > and can hand you the code if you want. It's
> probable a bit
> > stale
> > > vs the
> > > > current kernels and leaks memory under some
> circumstances
> > but is
> > > > probably better than starting from scratch.
> > > > James
> > > >
> > > > References
> > > >
> > > > Visible links
> > > > 1.
> [4][6][7]http://wiki.xensource.com/xenwiki/XenUSBPassthrough
> > > > 2. mailto:[5][7][8]james.harper@xxxxxxxxxxxxxxxx
> > >
> > > References
> > >
> > > Visible links
> > > 1. mailto:[8][9]pasik@xxxxxx
> > > 2.
> [9][10]http://wiki.xensource.com/xenwiki/XenUSBPassthrough
> > > 3. mailto:[10][11]james.harper@xxxxxxxxxxxxxxxx
> > > 4.
> [11][12]http://wiki.xensource.com/xenwiki/XenUSBPassthrough
> > > 5. mailto:[12][13]james.harper@xxxxxxxxxxxxxxxx
> >
> > References
> >
> > Visible links
> > 1. mailto:[14]pasik@xxxxxx
> > 2. [15]http://wiki.xensource.com/xenwiki/XenVGAPassthrough
> > 3. mailto:[16]pasik@xxxxxx
> > 4. [17]http://wiki.xensource.com/xenwiki/XenUSBPassthrough
> > 5. mailto:[18]james.harper@xxxxxxxxxxxxxxxx
> > 6. [19]http://wiki.xensource.com/xenwiki/XenUSBPassthrough
> > 7. mailto:[20]james.harper@xxxxxxxxxxxxxxxx
> > 8. mailto:[21]pasik@xxxxxx
> > 9. [22]http://wiki.xensource.com/xenwiki/XenUSBPassthrough
> > 10. mailto:[23]james.harper@xxxxxxxxxxxxxxxx
> > 11. [24]http://wiki.xensource.com/xenwiki/XenUSBPassthrough
> > 12. mailto:[25]james.harper@xxxxxxxxxxxxxxxx
>
> References
>
> Visible links
> 1. mailto:pasik@xxxxxx
> 2. mailto:pasik@xxxxxx
> 3. http://wiki.xensource.com/xenwiki/XenVGAPassthrough
> 4. mailto:pasik@xxxxxx
> 5. http://wiki.xensource.com/xenwiki/XenUSBPassthrough
> 6. mailto:james.harper@xxxxxxxxxxxxxxxx
> 7. http://wiki.xensource.com/xenwiki/XenUSBPassthrough
> 8. mailto:james.harper@xxxxxxxxxxxxxxxx
> 9. mailto:pasik@xxxxxx
> 10. http://wiki.xensource.com/xenwiki/XenUSBPassthrough
> 11. mailto:james.harper@xxxxxxxxxxxxxxxx
> 12. http://wiki.xensource.com/xenwiki/XenUSBPassthrough
> 13. mailto:james.harper@xxxxxxxxxxxxxxxx
> 14. mailto:pasik@xxxxxx
> 15. http://wiki.xensource.com/xenwiki/XenVGAPassthrough
> 16. mailto:pasik@xxxxxx
> 17. http://wiki.xensource.com/xenwiki/XenUSBPassthrough
> 18. mailto:james.harper@xxxxxxxxxxxxxxxx
> 19. http://wiki.xensource.com/xenwiki/XenUSBPassthrough
> 20. mailto:james.harper@xxxxxxxxxxxxxxxx
> 21. mailto:pasik@xxxxxx
> 22. http://wiki.xensource.com/xenwiki/XenUSBPassthrough
> 23. mailto:james.harper@xxxxxxxxxxxxxxxx
> 24. http://wiki.xensource.com/xenwiki/XenUSBPassthrough
> 25. mailto:james.harper@xxxxxxxxxxxxxxxx
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