I have a customer who is looking at WAAS specifically for AutoCAD 2007. There is plenty of press about the application and how it re-writes the entire file upon each save action. This will clearly cause the WAE to repeat Cold transfers every time, virtually eliminating any DRE benefits.
What is Cisco doing on this and are there any other options aside from looking at silverpeak who claim they can overcome this?
In March 2008 Autodesk changed the DWG file format for AutoCAD 2007 to make it more compact and improve performance for AutoCAD users. One of the side effects of the DWG format changes is that when users perform a complete save from within AutoCAD (as opposed to an "incremental" save), virtually every byte of the file gets changed - even if zero changes were made to the file itself. The effect of the new file format, is that in some scenarios where the default configuration of the Autodesk save is modified, the save of the file object will render the caching / optimization less effective.
When the setting of ISP is set to deault, WAAS provides great performance improvement (~8x acceleration for some operations), but when the ISP is set to 0, Performance improvement may be lower.
We have performed several tests in our lab, with ~12MB file with Autocad08, ISP=50 over T1, 80msec link, we were able to reduce the second time open of the file from ~200sec (native) to ~25sec (cache hit), and the save operation (small modification to the file and save) took ~25sec vs. ~240sec over native WAN. The optimizations are both generic DRE compression (since with ISP=50 the DRE is VERY effective) and CIFS optimizations (based on the CIFS cache). The compression was high, above 90%
When ISP was set to 0, forcing the re-encoding of the whole file, and rendering the DRE compression was less effective, the following results has been inspected:
Compression ~10%. The save operation is reduced by ~40%, from 125sec to ~80sec
Check out the following article
Although the title suggests "issues with Cisco WAAS", the actual content of the article takes a reasonably balanced view of Cisco WAAS and positions it positively with these facts:
1. Even when AutoCAD ISP value is set to 0, forcing fresh download every time, Cisco WAAS still provides noticeable optimization. When ISP is set to default 50, which most customers do, Cisco WAAS provides 90.05% optimization.
2. In addition, the 9.43% bandwidth optimization was based on Novell file server, hence the CIFS optimization technique on WAAS was not leveraged.
3. If CIFS optimization is leveraged, such as the CIFS-based AutoCAD testing in Cisco lab, Cisco WAAS shows 40% response time saving, even when AutoCAD ISP is set to 0.