Saturday, March 8, 2008

AutoCAD 2007 File format and WAN Acceleration

I was at the AIA Large Firm Rountable CIO meeting this pasgt week in NYC and one of the discussions was the problem with the AutoCAD 2007 file format and the problems that it has created for WAN Acceleration tools like Riverbeds. I am not going to try to get into all the technical details, but apparently the AutoCAD 2007 file format uses a new compression scheme that basically reorganizes the file each time you save. Because of this WAN Accelerators are not able to identify patterns in the file as well and WAN Acceleration is severely impacted.

Autodesk and Riverbed are aware of the problem, but Autodesk has not provided a fix at this time. It was suggested at the meeting that if Autodesk could provide an option in the next release (2010 - as 2009 products are in beta) that would allow the user to disable the new compression, this would resolve the problem.

This is an issue on all the AutoCAD based applications, such as AutoCAD Architecture, AutoCAD MEP, etc.

1 comment:

Marie said...

Potential for reduced write performance for Riverbed WAN links when working with AutoCAD 2007 DWG files

Published date: 2008-Mar-12
ID: TS1082827

Applies to:
AutoCAD® 2008
AutoCAD® 2007
AutoCAD® Architecture 2008
Autodesk® Architectural Desktop 2007
AutoCAD® Civil 3D® 2008
Autodesk® Civil 3D® 2007

Issue
In March 2006, Autodesk changed the DWG file format for AutoCAD 2007 to make it more compact and improve performance for AutoCAD users. Autodesk’s customers widely welcomed this change and almost all AutoCAD users have enjoyed improved performance.


Solution
However, Autodesk and Riverbed have recently received reports that some customers using some WAN acceleration appliances, including Riverbed’s Steelhead appliances, have experienced noticeable reductions in write performance when working with files saved in the AutoCAD 2007 “DWG” format. 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 net effect is that writes that would normally affect only “warm” data are actually “cold”, due to the reordering of the data in the file.

Users of Riverbed or other affected WAN acceleration solutions can implement the following immediate workarounds that improve write productivity.

1. Using a feature in AutoCAD called “Incremental Save Percentage” (ISP), and setting it to 50

2. Using a version of the DWG format other than the AutoCAD 2007 DWG format

The performance and productivity of our customers is a key consideration for Autodesk and Riverbed. For this reason, our engineering teams are working together to devise workarounds and are examining potential longer-term solutions. Given Riverbed’s experience in WAN acceleration technology, our joint work may also provide solutions for customers of other WAN acceleration or deduplication technologies, who might be experiencing similar issues with write performance. We will provide information on those developments at a later date.

In the meantime, customers should contact Autodesk or Riverbed customer support with any questions, or visit www.autodesk.com/support.

http://usa.autodesk.com/adsk/servlet/ps/item?siteID=123112&id=10901842&linkID=9240617

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