Xen users - Mar 2011 - physical network card assigned to the domU can optimize the performance?

hi.

I have a SAMBA PDC on a domU.  The users are experimenting low performance
when use the apps stored in the server (access databases).

The first discard was assign exclusives CPU''s to the domU.

kernel      = ''/boot/vmlinuz-2.6.26-1-xen-686''
ramdisk     = ''/boot/initrd.img-2.6.26-1-xen-686''
memory      = ''2048''
cpus        = ''4-6''
vcpus        = ''3''


Initially i was use file-backed image, but change all to physical partition
and tap:aio images.


This is my actual config:

root        = ''/dev/sda2 ro''
disk        = [
                 
''tap:aio:/opt/xen/domains/samba/swap.img,sda1,w'',
  ''phy:/dev/sda6,sda2,w'',
  ''tap:aio:/opt/xen/domains/samba/home.img,sda3,w'',
  ''phy:/dev/disco-c/disco-c,sda4,w'',

Now all the performance test show very good results, but the users continue
experimenting slow access.

i run that command on domU


ethtool -K eth0 tx off

and apparently the performance was improved.

My last idea is dedicate a physical network card to that domU.  But really
that can optimize the access?

I have 3 domUs in the same server, but the samba require the best access,
because all the users work permanently on that (the others domUs are mail
server and Web server).

really assign a dedicated network card to the domU can optimize the access?

Any another idea to discard?

thanks and regards.


_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

On Sat, Mar 12, 2011 at 5:11 AM, kazabe <kazabe@gmail.com>
wrote:
> hi.
> I have a SAMBA PDC on a domU.  The users are experimenting low performance
> when use the apps stored in the server (access databases).
> The first discard was assign exclusives CPU''s to the domU.
> kernel      = ''/boot/vmlinuz-2.6.26-1-xen-686''
that is old (is it even maintained?), and has known bugs
> ethtool -K eth0 tx off
... like this one. Or it could just be your NIC is flakey.

I''v been using RHEL with Broadcom (tg3 and bnx2 driver), and
hasn''t
seen this problem in long time. It works fine with bridge setup.
> Any another idea to discard?
Dump the kernel. Choose something else that works.

Either use an OS with tested Xen bundle (I use RHEL5.6) or compile
your own xen and dom0 kernel.

Normally I''d suggest upgrading your OS (is it Lenny?), but bundled Xen
in Squeeze does not have tap:aio support. You could probably make it
work by rebuilding xen userland package with a patch though (search
this list archive, it''s mentioned not long ago).

-- 
Fajar

_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users