On Wed, Mar 07, 2012 at 05:57:45AM -0800, THO HUYNH wrote:
> I tried to copy file from host to the running guest after I had
> mounted the guest but it`s seemed slow.  The speed is about 6-8
> MB/s. I thought it would be the same with real hard drive (about
> 20MB/s).

Is this using 'guestmount --live'?

Unfortunately FUSE is inefficient, particularly the way we implement
it in guestmount.

If you use 'guestfish --live' and the 'upload' command, you should be
able to get full disk speed easily.

> If I have more than one guest, will they share the 6-8 MB bandwidth ?

If the guest storage is on different spindles, then you should be able
to max out each spindle (using guestfish, not guestmount).  If they
all share the same disk spindle, then of course it will share the disk
bandwidth.

> Are there anyway to improve the performance ?

Definitely use guestfish, or the libguestfs API directly.

If you want to copy in large amounts of data, then *sometimes* it can
be advantageous to prepare an ISO containing the data in advance:

http://libguestfs.org/guestfs.3.html#uploading

but you should measure it because it might not actually be faster,
since uploads use virtio-serial which is very fast.

Rich.

--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
virt-top is 'top' for virtual machines.  Tiny program with many
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