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I have just configured a XenServer 6.2.0 (based on CentOS) host in a server with 2 high-end processors, 256 GB RAM and SSD storage. The distribution is up to date.

We set up several virtual machines and every expected functionality is working properly but I have concers about the speed of the network communication among VMs inside the host (for example, transferring one file using scp from one VM to another).

These are the numbers I got:

  • Ping response time: 0.5 ms
  • Transfer rate (big files): 50 MB/s

I have no previous experience with virtualization technologies, so I don't know if this numbers make sense. Do they make sense? Is usually internal network that slow?

I try several changes with no effect on speed:

  • Installing or deinstalling xen-tools
  • Using a single-server private network
  • Disabling ethernet offload

Any light on this would be appreciated. Thanks, Jose

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How did you test your network speed? – ETL Mar 3 '14 at 15:07
Ping is just a ping from one VM to another. Transfer rate is given by a transfer of one 1GB file from one VM to another using scp. In both cases the private network is used. – user211430 Mar 5 '14 at 9:34
What are the operating systems of the VMs? – pepoluan May 18 '14 at 18:54

It sounds to me like the VMs are routing outside of the XenServer Host, to your router, then back to the VMs within the host. What is the backbone speed of the network that your host is connected to?

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