[CentOS] Any HowTo for Getting Started With Xen?

[Luciano Rocha]

On Mon, May 28, 2007 at 05:53:50PM +0100, Karanbir Singh wrote:
>  Luciano Rocha wrote:
> > You can't. Xen's fully virtualized hardware implementation isn't as fast
> > as VMware's. Also, there are no para-virtualized drivers for HDD, lan or
> > video for Windows, as there are in VMware.
> 
>  Do you have any details or stats on this claim that Xen's full-virt isnt as 
>  fast as VMware's ?

No, no benchmark. My hardware doesn't support VT, and I haven't been
allowed sufficient time for doing proper benchmarks on hardware that do
support it.

My opinion is based on what I've read in xen's lists. That current qemu
hw emulation and vm implementation requires several trips between
dom0 and domU for a *single* request. And some user cases where network
throughput is in the *Kbps*.

This isn't the case if you have access to VirtualIron or Xen Enterprise,
that provide para-virtualized drivers (for Windows; for Linux there is
already source code in the tree).

> Based on what I've seen Xen's full-virt is actually a 
>  fair bit faster than vmware.

If the bottleneck is CPU or memory, xen will be faster. But I/O will be
very slow, compared to VMware (mayben even without vmware drivers
installed, as it at least emulates a scsi controller).

> Besides para-virt on Xen is many many times 
>  more efficient than vmware's machine emulation.

That's true, and I mentioned that in my email.

Also, you can't use VMware under xen (unless in a fully-virtualized
guest), but you can use xen under VMware (but don't expect great
performance).

-- 
lfr
0/0
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: not available
URL: <http://lists.centos.org/pipermail/centos/attachments/20070528/b0b2543c/attachment.sig>