SMB 2.0 Tuning for Citrix XenApp 6.x


More and more people are moving their file servers to Windows 2008. For this reason it’s essential to do some SMB 2.0 tuning in the registry to get the best possible performance with Citrix XenApp 6.x.

SMB 1.0 was originally designed 15 years ago and was introduced with Windows 3.11 for Workgroups. Since the fastest networks in use at the time generally offered a maximum transfer rate of 10 Mb/s, the protocol has become out of date.

Indeed, with Gigabit Ethernet interfaces now a common feature even on budget motherboards, SMB can’t keep up with current network speeds.

SMB 2.0 is the new version of SMB that has been redesigned for today’s networking environments and the needs of the next generation of file servers. SMB 2.0 has the following enhancements:

  • Supports sending multiple SMB commands within the same packet. This reduces the number of packets sent between an SMB client and server, a common complaint against SMB 1.0.
  • Supports much larger buffer sizes compared to SMB 1.0.
  • Increases the restrictive constants within the protocol design to allow for scalability. Examples include an increase in the number of concurrent open file handles on the server and the number of file shares that a server can have.
  • Supports durable handles that can withstand short interruptions in network availability.
  • Supports symbolic links.

SMB 2.0 seems to perform significantly faster than SMB 1.0 under optimal circumstances. I’ve heard of improvements ranging from 50% faster to 3500% faster. The bad news is that, as you might expect, you have to have SMB support on both ends of the communications pipe for SMB 2.0.

SMB 2.0 Tuning File Server :

Our XA5/XA6 Group Policy Tuning Templates have been downloaded more than 12.609 times. The SMB 1.0 tunings are ready-to-go as long as you set the values on your File Server(s) correctly. If you’re running a pure SMB 2.0 environment there’re still some SMB 2.0 Tuning needed. These registry keys needs to be added to your File Server(s).

SMB 2.0 Tuning Citrix XenApp 6.x Servers :

All credits for this article goes to Dan Allan from Citrix Consulting. Make sure you check out his in-depth article SMB Tuning for XenApp and File Servers on Windows Server 2008 over at Citrix Blogs.

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7 thoughts on “SMB 2.0 Tuning for Citrix XenApp 6.x”

  1. Hi,
    Has anyone come across this:;EN-US;2536487
    I am dealing with a very high visibility, highly escalated crisis – per this article you can no longer publish apps from (file server) UNC paths. To me, this is pretty major in XenApp architecture. Microsoft claim this effects 2008 and 2008 R2.
    Any thoughts, opinions or contradictions – much appreciated!

    • Hi Ofer. I got many customers still running apps from UNC path, both as publish applications and within the publish Desktop without any problems. So I would believe this is vendor problem rather than a Citrix/Microsoft problem. Does it work on a Win 7 machine from the same UNC path?

  2. Hi there,
    Same here I have many customers in the past running with the same configuration. My client is the vendor and so far all traces and debugs show’s it is not the application but the OS’s (TS and File Server both 2008 not R2). I am in a complex environment that doesn’t allow me to load up a Windows 7 machine into the app environment – however this is a conclusion from a Microsoft Severity A case escalation just this weekend. They are saying flat out “This configuration is no longer supported – UNC’s published apps that is”. Since, I have deployed many applications in this configuration, in the past successfully. I am having a real hard time digesting this too. Also I should mention I am in a large hosted environment where I have direct access to the vendor and its entire product development team for full view/debugging “under the hood” of the application. I will update when/if I receive more info. Currently I am looking at a possible re-architecture of the entire app deployment as a result of this article. If this is true (which I am seriously doubting) this has major impact to all us Citrix publishers out there….

  3. Same question as Jan.

    With a Xen App 6.5 farm running on Win. 2008-R2, any tuning for 2012-R2 files server ?



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