Hi,
I've setup a Xen server host (suse, xen 3.0.2) with vlan as follows:
server-eth0 <-> vlanXY <-> vbridgeXY <-> domU-eth0
That is: vlan's are managed in the physical host (for better security).
The setup is working, i.e. I can connect to/from domU-eth0 from hosts in
the same vlan.
The problem is: it seems I loose "many" packets.
I've run "ttcp"[*] tests between:
A)- 2 physical hosts on that vlan
B)- physical and domU hosts on that vlan (here physical host is not the
Xen server)
Dom0 host is quite powerful... more than any physical host I've tried to
connect to and is acting as the receiver in "ttcp" tests.
The network where the vlan traffic goes is a Gbit.
Well, in UDP tests I've discovered that a certain amount of packets get
lost. Results are:
in case A) 100% bytes transferred are received
in case B) 4% bytes transferred are lost [**]
Could that "4%" be considered acceptable for Xen?
For example: XenEnterprise 3.2 (to be released 31th March) will do
better? (it has support for vlan AFAIK). Someone has got some numbers?
Others check I've run:
C)=> 2 physical hosts on the same vlan, one of which is the Xen server:
100% bytes transferred are received !!!!!
D)=> Under vmware esx v3 I've got (different machine, same hardware):
0.8% bytes transferred get LOST (same vlan).
Yes, they loose something but not 4% of udp network traffic
Has someone else tested that vlan setup under xen? And what numbers have
you got?
[*]: ttcp is a tool for testing the throughput of tcp/udp connections.
See for example here for packages in rpm:
http://rpmseek.com/rpm-pl/ttcp.html?hl=com&cs=ttcp:PN:0:0:0:0
Typical ttcp commands I've run:
1) server listening (ip on vlanXY):
ttcp -u -s -r -f M -n 50000
2) client sending data (ip on vlanXY):
ttcp -u -s -t -f M -n 50000 <other_ip_on_vlanXY>
As for TCP traffic, probably because of packet loss network throughput
is somewhat lower than expected.
[**]: actually it's a value around 4%, but after many tests that value
could be considered an acceptable average.
Regards,
--
-- Marco Mililotti
"Democracy is two wolves and a lamb voting on what to have for lunch.
Liberty is a well-armed lamb contesting the vote."
Benjamin Franklin
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