Yorkshire Cloud’s engineers recently had quite a tricky problem with AutoCAD performance in our XenApp-based hosted desktops. For weeks it had us stumped, but our team don’t like to give up!
The problem was that in complex AutoCAD drawings, especially ones with blocks and hatching, the mouse had a tendency to lag and drift across the screen. Sometimes it would take several seconds before the user could get control of the mouse again. The mouse didn’t do this all the time, although the problem was severe enough to make AutoCAD virtually unusable.
We had seen AutoCAD running perfectly well in other XenApp environments, so we knew it was possible to fix this issue. We diligently followed all the advice we could find online, including turning off most of AutoCAD’s graphics intensive features. Unfortunately, none of the recommendations had any effect.
We had also given the server more RAM and CPU than it knew what to do with! Apparently under-specced servers are a common cause of AutoCAD performance issues.
Lesson: If all else fails, use a process of elimination.
After weeks of hard work, we were close to running out of ideas. Instead we tried to do a process of elimination. It would be time consuming but we didn’t want to let our customer down. We decided to experiment with a wide range of Citrix policies, Windows settings and Group Policy Objects.
In the end, we were able to pinpoint the root cause of the AutoCAD issue – it was the Citrix Desktop Viewer. This is a handy utility which allows the hosted desktop windows to be resized dynamically. It also provides a useful black toolbar at the top of the screen which allows users to easily switch back and forth between their local computer and their hosted desktops.
We found that with Desktop Viewer enabled, AutoCAD performed poorly. But with it disabled, AutoCAD was perfectly fine. More than fine, in fact. We found that we could enable all of AutoCAD’s graphics-intensive features with no issues. We found this quite impressive, especially considering we weren’t using a dedicated graphics card.
For the more technically minded of you, you can enable/disable the Desktop Viewer by editing the webinterface.conf file on the Web Interface server. See the Citrix blog post here. Desktop Viewer was originally a feature of XenDesktop, but from early 2011 Citrix added experimental support for it in XenApp too. In summer 2012, with the release of Citrix Receiver 3.3, Citrix started officially supporting the use of Desktop Viewer in XenApp environments.
It came as a huge relief to solve this problem. AutoCAD is a core application for one of our customers. Without AutoCAD, their business struggled to function. It surprised us that no-one else seemed to have encountered this issue, which is why we’ve decided to write this blog post.
We do have a slight problem: Desktop Viewer can only be enabled or disabled for the whole Yorkshire Cloud environment, meaning it affects all of our customers. But some of our customers quite liked the Desktop Viewer’s toolbar. As a workaround, users can get back to their local desktop by pressing SHIFT + F2.
Needless to say, we have raised this issue with Citrix Support and are hoping they can fix it soon.
In the meantime, our team of talented Yorkshire Cloud engineers can feel satisfied that we’ve defeated one more IT gremlin. Persistence pays off!
Photo Credit: Markheybo