Slow transfers between VM & HOST on Workstation 7.1.4

[kumar981]

Hello Community,

I have installed Workstation 7.1.4 on Windows 7 64 Bit with 1Gbps LAN card. I have created a VM for WinXP SP3 32 bit with SCSI virtual HDD and assigned 2 cores to the vm. I intially faced a lot of problem sharing files as the transfer rates were only in KB/s. I researched the community and figured that disabling the "Large Send Offload" will improve transfer speeds and sure enough, it worked.

However, the transfer speed is now 12MB/s, which is still way below 1Gbps connection. I have tested with "iperf" utility and found that the transfer rates between the host and vm is around 150Mbps on an average. I have tried diabling Antivirus, Firewalls on both the vm and host but the speed remains in 150 Mbps range. I even created a new vm and tested it and that too, is transferring at 150Mbps.

Any suggestions would really be helpful.

Thanks

[Scissor]

iperf is a good utility to test raw network speed.  At higher network speeds the CPU becomes the limiting factor.  Guests with 2 or more vCPUs can cause scheduling delays on the Host, which might affect raw network transfers. 

Try changing your Guest VM to have only 1 vCPU and test again. 

[kumar981]

Thanks Scissor. The results are the same even with 1 vCPU. Transfer rates are still at 120-150 Mbps.

[Scissor]

Can you share the iperf command line that you are running?  I assume that your Host is configured as the iperf server?

Here is my output from running "iperf -s" on my Win 7 Host, and "iperf -c <host_ip>" on a WinXP Guest:

C:\Temp>iperf -c xxxxxxx

------------------------------------------------------------

Client connecting to xxxxxx, TCP port 5001

TCP window size: 8.00 KByte (default)

------------------------------------------------------------

[1856] local 10.102.151.103 port 4455 connected with 10.102.151.12 port 5001

[ ID] Interval       Transfer     Bandwidth

[1856]  0.0-10.0 sec   287 MBytes   240 Mbits/sec

[kumar981]

Hi Scissor,

Here's the output from my XP VM. The host is running "iperf -s"

C:\Temp>iperf -c 10.119.198.100

[Scissor]

Looks like your last post was cut off at the bottom or something.

[kumar981]

Hi Scissor,

Here's the output from my XP VM again. The host is running "iperf -s"

C:\Temp>iperf -c 10.119.198.100