Re: [Xen-users] Windows 2008 - slow upload

[Matthias Reif <mattreif@xxxxxxxxxxxxx>]

xen-users-bounces@xxxxxxxxxxxxxxxxxxx wrote on 03/08/2009
07:50:09 PM:

> -------- Original Message  --------
> Subject: Re: [Xen-users] Windows 2008 - slow upload
> From: Stephen Ross <stephen.ross1986@xxxxxxxxxxxxxx>
> To: Tomek <timor@xxxxx>
> Date: 03.08.2009 11:32
> 
> > Hi Tomek,
> > 
> > Where are you uploading to? I have been having very similar issues
to 
> > you, however I've found that my issues are specific to certain
hosts on 
> > my network.
> > 
> > Do other DomU's on the same host get the same issues?
> 
> Good tip. I could upload to another Win2k8 based VM on the same xen
> machine with normal speed, but when uploading to different physical
> server in the same network speed decreased.
> 
> Tell me more about your problem :)
> 
> Maybe it's not optimal VLAN's configuration.
> 

Hi Tomek,

This might be a long shot, but do you have the recently
released service pack 2 for Server 2008 installed?

I had a Server 2008 domU happily uploading (domU->dom0)
at 60-80 MB/s until I started seeing similar symptoms to what your are
describing (dom0->domU ok 60-80 MB/s, domU->dom0 poor 2-4 MB/s or
even less). The start of these symptoms coincided with the installation
of SP2.

I haven't uninstalled SP2 to confirm yet as I wanted
to do some troubleshooting first. I found that TCP transmissions from domU
to dom0 seem to pause in regular intervals for 0.5 up to 2 seconds, bringing
the average transmission speed of large data volumes down to an unacceptable
level.

dom0: CentOS 5.2, Xen 3.3.1
domU: Windows Server 2008 64-bit SP2, GPLPV 0.10.0.69

Below are the results of a test that I was doing using
TTCP and TCPDUMP. Note the timestamps and how the transmission seems to
freeze for up to 2 seconds before continuing.

06:39:33.772162 IP 10.230.11.41.commplex-link >
10.230.11.42.51543: . ack 5554177 win 65535
06:39:33.772280 IP 10.230.11.42.51543 > 10.230.11.41.commplex-link:
P 5554177:5562369(8192) ack 1 win 64240
06:39:33.772300 IP 10.230.11.41.commplex-link >
10.230.11.42.51543: . ack 5562369 win 65535
06:39:34.126764 IP 10.230.11.42.51543 > 10.230.11.41.commplex-link:
P 5562369:5570561(8192) ack 1 win 64240
06:39:34.126793 IP 10.230.11.42.51543 > 10.230.11.41.commplex-link:
P 5570561:5578753(8192) ack 1 win 64240
06:39:34.126857 IP 10.230.11.41.commplex-link >
10.230.11.42.51543: . ack 5570561 win 65535

[...]

06:39:34.182774 IP 10.230.11.42.51543 > 10.230.11.41.commplex-link:
P 6545409:6553601(8192) ack 1 win 64240
06:39:34.182794 IP 10.230.11.42.51543 > 10.230.11.41.commplex-link:
P 6553601:6561793(8192) ack 1 win 64240
06:39:34.182808 IP 10.230.11.41.commplex-link >
10.230.11.42.51543: . ack 6561793 win 65535
06:39:35.477353 IP 10.230.11.42.51543 > 10.230.11.41.commplex-link:
P 6561793:6569985(8192) ack 1 win 64240
06:39:35.477375 IP 10.230.11.42.51543 > 10.230.11.41.commplex-link:
P 6569985:6578177(8192) ack 1 win 64240
06:39:35.477470 IP 10.230.11.41.commplex-link >
10.230.11.42.51543: . ack 6578177 win 65535

[...]

06:39:35.506777 IP 10.230.11.42.51543 > 10.230.11.41.commplex-link:
P 7413761:7421953(8192) ack 1 win 64240
06:39:35.506800 IP 10.230.11.42.51543 > 10.230.11.41.commplex-link:
P 7421953:7430145(8192) ack 1 win 64240
06:39:35.506813 IP 10.230.11.41.commplex-link >
10.230.11.42.51543: . ack 7430145 win 65535
06:39:37.477564 IP 10.230.11.42.51543 > 10.230.11.41.commplex-link:
P 7430145:7438337(8192) ack 1 win 64240
06:39:37.477601 IP 10.230.11.42.51543 > 10.230.11.41.commplex-link:
P 7438337:7446529(8192) ack 1 win 64240
06:39:37.477712 IP 10.230.11.41.commplex-link >
10.230.11.42.51543: . ack 7446529 win 65535

[...]

06:39:37.505504 IP 10.230.11.42.51543 > 10.230.11.41.commplex-link:
P 8282113:8290305(8192) ack 1 win 64240
06:39:37.505526 IP 10.230.11.42.51543 > 10.230.11.41.commplex-link:
P 8290305:8298497(8192) ack 1 win 64240
06:39:37.505539 IP 10.230.11.41.commplex-link >
10.230.11.42.51543: . ack 8298497 win 65535
06:39:39.463085 IP 10.230.11.42.51543 > 10.230.11.41.commplex-link:
P 8298497:8306689(8192) ack 1 win 64240
06:39:39.463117 IP 10.230.11.42.51543 > 10.230.11.41.commplex-link:
P 8306689:8314881(8192) ack 1 win 64240
06:39:39.463249 IP 10.230.11.41.commplex-link >
10.230.11.42.51543: . ack 8314881 win 65535

Thanks
Matthias



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