Citrix XenServer – Make your network 10x faster


When putting most of your workloads on a Hypervisor you should not take for granted that you automatically get the maximum performance out of the box. You as the administrator need to perform additional tests to verify that the network performance are at it’s best.

Last week I upgraded my Citrix XenServer Home Lab and gained 10x faster network performance. In this blog post I’ll show you how you can run some simple tests to accomplish the same.

So I started testing Network Throughput Using Iperf. The Virtual Machines where 2 vanilla Windows 2008 R2 hosted on Citrix XenServer 5.6 SP2 with all hotfixes applied.

As you can see from the image above the bandwidth is around 31 Mbytes/sec.

When running the same Virtual Machines on Citrix XenServer 6.1 with all hotfixes applied I got 60 Mbytes/sec on average. This makes sense as described in this article regarding the importance of keeping the network drivers up to date.

Since Windows 2008 R2 is using SMB 2.0 I wanted to test Windows 2012 which leverages SMB 3.0

Check that out, the network is 10x faster on the latest version of Citrix XenServer and Windows 2012. So needless to say, all my servers have now been upgraded to Windows 2012.

I also wanted to try out the free Microsoft Hyper-V Server 2012 on my old hardware to see if there where any performance difference between XenServer and Hyper-V. With 2 vanilla Windows 2008 R2 I got 205 MBytes/sec.

This is just an example to demonstrate the importance of doing proper testing. My lab hardware is not on the Citrix XenServer HCL and the RealTek network adapter has caused problems on many XenServer builds.

When you’re on it, make sure you get good performance between 2 VM’s hosted on different hypervisors since the traffic goes through your switches and not internally.

With the introduction of my new App-V 5 Training Course I teach you how to leverage Share Content Store in VDI / SBC. Since the App-V 5 applications are streamed directly 10x faster network means everything for the end user experience.


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Friday 30th of September 2022

13 thoughts on “Citrix XenServer – Make your network 10x faster”

  1. I also noticed a huge difference with Server 2012 on the latest Xen 6.1 up to HF17 then with the vanilla 6.1. Now if Citrix would just Complete and Certify an official XenTools.

  2. When you say you updated all your servers to 2012, you mean all except those running XenApp 6.5 I guess ? So any SMB connection originating from your XenApp servers would still be using SMB 2.1.

  3. Any incompatibilty between WIN2K12 and PVS XA XD inside XenDesktop7.
    I heard somewhere XA app streaming is not supported with WIN2K12

  4. I believe your test lab equipment is using a Gigabit networking card. Gigabit network cards have a theoretical maximum bandwidth of ~125MBytes/sec, yet your iperf results are showing over ~419 MBytes/sec or ~3.3 Gbps. What part of the SMB3 protocol is tripling the theoretical maximum of Gigabit networking.

  5. This may not be the right place or time for this comment but I’m trying to setup a server in xenapp so I can run multiple VMs. My host OS is W2k12. I have IIS using the port I think so I’m unable to connect to the server. Would it be better to turn off IIS feature? Or can I have both sharing the same port? Its all very confusing so any help would be much appreciated. I just wanna be able to host websites and applications on multiple servers but not sure what would be an ideal setup or how to go about it.

  6. The VM’s report only 1 Gb spped though XenServer has 10 GBps NIC’s. As per XenServer Documentation its normal. However will my Vm’s go beyond 1 GBps if there is a demand?


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