Re: [Xen-users] Network performance in virtual machine (good upload speed, bad download)

[Martin Nilsson <martin@xxxxxx>]

This is my output from ifconfig:

lucy:~# ifconfig
eth0      Link encap:Ethernet  HWaddr 00:02:A5:0D:09:32
          inet addr:192.168.1.10  Bcast:192.168.1.255  Mask: 
255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:5951 errors:23 dropped:23 overruns:0 frame:23
          TX packets:3630 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:7130145 (6.7 MiB)  TX bytes:378644 (369.7 KiB)

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:3606 errors:0 dropped:0 overruns:0 frame:0
          TX packets:3606 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:269811 (263.4 KiB)  TX bytes:269811 (263.4 KiB)

vif1.0    Link encap:Ethernet  HWaddr FE:FF:FF:FF:FF:FF
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:2547 errors:0 dropped:0 overruns:0 frame:0
          TX packets:4773 errors:0 dropped:199 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:175603 (171.4 KiB)  TX bytes:6725419 (6.4 MiB)

xen-br0   Link encap:Ethernet  HWaddr 00:02:A5:0D:09:32
          inet addr:192.168.1.10  Bcast:192.168.1.255  Mask: 
255.255.255.255
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:1196 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1085 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:140820 (137.5 KiB)  TX bytes:203365 (198.5 KiB)

Should I perhaps try a lower MTU? I've never worked with bridges in  
Linux before, so I'm not sure.
Best regards,
/Martin


28 nov 2005 kl. 01.45 skrev Stephan Seitz:

> hi,
>
> networking problems with large MTU's have been recently discussed on
> the xen-devel list.
> i don't know if this is also relevant for xen 2.0.7, but as a first
> step, i would take a look of
> the bridge's MTU as well as of the virtual eth device in the domU.
>
> greetings
>
> stephan
>
>
>
> Martin Nilsson schrieb:
>
> > I have just installed Xen and got a virtual machine up and running.
> > Everything seems to work fine, except that I get strange network
> > performance in the virtual machine. When I upload data, I get good
> > speeds, around 6-7 MB/s which I think is ok on a 100 Mbit network.
> > When I download however, I only get ~300 KB/s. On the host machine
> > I get good speed in both direction. The version of Xen is 2.0.7,
> > and I have tried both the binary release and built my own kernel,
> > with the same results. The host OS is debian sarge. I really have
> > no idea where to look for a solution, so every advice I can get is
> > highly appreciated.
> >
> > Best regards, /Martin
> >
> > _______________________________________________ Xen-users mailing
> > list Xen-users@xxxxxxxxxxxxxxxxxxx
> > http://lists.xensource.com/xen-users
>
>
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