WAN Acceleration 2009 Hotfix

Autodesk finally released a hotfix to improve the performance of saving to 2007 DWG format when running in a WAN Acceleration environment. The problem was an Autodesk problem, and not anything related to any particular Wan Accelerator as some people have thought. This is a Hotfix posted by Autodesk that you can also view from the following links...

2009 Wan Acceleration Hotfix link
2008 Wan Acceleration Hotfix link
2007 Wan Acceleration Hotfix link


Description of Problem
WAN acceleration technology typically relies on data-deduplication as a significant part of accelerating data transfer. The 2007 DWG format is written to disk with a type of error-checking that has the side-effect of nearly every byte of the file changing during full-save, even if little was changed. WAN accelerators fail to deduplicate the 2007 DWG data and must transfer nearly all bytes in the 2007 DWG file. This results in a slow-down during full-save when working over a slow WAN.

This hotfix will make a small change in the way the 2007 format DWG files are written to disk such that WAN acceleration hardware will be better able to deduplicate the 2007 DWG data; this will provide some performance gains for SAVE operations when users are saving across a WAN acceleration environment. The resulting 2007 DWG file will be readable whether or not others have this hotfix, but to achieve the best performance everyone working on the same DWG should install this hotfix.

After intalling the hotfix, you must set the Windows environment variable, ACADCOMPRESSIONMODE to 1 for it to have effect.

Note: For AutoCAD, you can often get performance gains in QSAVE operations by setting the ISAVEPERCENT system variable to 100. Using a value of 100 will maximize the chance that a QSAVE operation will use incremental-save rather than full-save. (WAN accelerator technology is able to show good performance in deduplication of 2007 DWG format files when incremental save takes place.)

Applicable Products
AutoCAD 2009
AutoCAD LT 2009
AutoCAD Architecture 2009
AutoCAD Civil 3D 2009
AutoCAD Electrical 2009
AutoCAD Land Desktop 2009
AutoCAD Map3D 2009
AutoCAD Mechanical 2009
AutoCAD MEP 2009
AutoCAD P&ID 2009
AutoCAD Raster Design 2009
AutoCAD Revit Architecture Suite 2009 (1)
AutoCAD Revit MEP Suite 2009 (2)
AutoCAD Revit Structure Suite 2009 (1)
Autodesk Inventor™ Professional 2009 (3)
Autodesk Inventor Suite 2009 (3)

(1) Apply this hotfix only if the installation includes AutoCAD 2009.
(2) Apply this hotfix only if the installation includes AutoCAD MEP 2009.
(3) Apply this hotfix only if the installation includes AutoCAD Mechanical 2009 or AutoCAD Mechanical Desktop® 2009.

Installation Instructions

To Install the WAN Acceleration Hotfix
You must have administrative privileges on your Microsoft® Windows® operating system to complete the installation process.

This installation requires you to replace the following files:

• acdb17.dll
• AcSignCore16.dll

After you replace these files, you must restart your system in order for this hotfix to take effect.

NOTE: Only apply this hotfix after you have installed an AutoCAD 2009-based product. This installation requires you to modify an installed product, which may cause Windows security warnings to display. For all Windows security warnings that display during installation, click Continue.

To Replace the acdb17.dll File

1. Close all software applications.
2. Navigate to your product installation folder; for example C:\Program Files\AutoCAD 2009.
3. In the product installation folder, right-click the acdb17.dll file and select Properties.
4. Click the Version tab and confirm the file version.
5. If the file version is 17.2.56.0, 17.2.111.0, or 17.2.112.0, proceed with this installation.
6. If the file version is greater than 17.2.112.1, do not install this hotfix.
7. Rename the affected original file.
8. In the product installation folder, right-click the acdb17.dll file and rename it acdb17.bak.
9. Based on the product you have installed and its version of the acdb17.dll file, double click the appropriate file.
10. For AutoCAD 2009-based products with the acdb17.dll file version 17.2.56.0
11. Based on the version of your product, double-click WAN_Accelerator_Hotfix_2009_32bit.zip or WAN_Accelerator_Hotfix_2009_64bit.zip.
12. For AutoCAD 2009 Update 1 with the acdb17.dll file version 17.2.111.0 or 17.2.112.0
13. Based on the version of your product, double-click WAN_Accelerator_Hotfix_2009_Update_1_32bit.zip or WAN_Accelerator_Hotfix_2009_Update_1_64bit.zip.
14. Extract acdb17.dll file to the product installation folder; for example C:\Program Files\AutoCAD 2009. NOTE: Keep the zip file that you used in step 6 open. Without opening other software applications, immediately proceed to the procedure below .

To Replace the AcSignCore16.dll File

1. Navigate to your Autodesk Shared folder; for example: C:\Program Files\Common Files\Autodesk Shared.
2. In Autodesk Shared folder, right-click the AcSignCore16.dll file and select Properties.
3. Click the Version tab and confirm the file version.
4. If the file version is 17.2.56.0 proceed with this installation.
5. If the file version is greater than 17.2.112.1, do not install this hotfix.
6. Rename the affected original file
7. In the Autodesk Shared folder, right click the AcSignCore16.dll file and rename it AcSignCore16.bak.
8. Double-click the zip file you used when you replaced the acdb17.dll file. See To Replace the acdb17.dll File, Step 6.
9. Extract the AcSignCore16.dll file to the Autodesk Shared folder; for example: C:\Program Files\Common Files\Autodesk Shared.
10. Restart your system.

To set the ACADCOMPRESSIONMODE environment variable

On Windows XP

1. Right-click My Computer, and then click Properties.
2. Click the Advanced tab.
3. Click Environment variables.
4. Click New to add a new system variable name and value.
5. Set the Variable name to ACADCOMPRESSIONMODE
6. Set the Variable value to 1
7. Click OK until you return to the desktop

On Windows Vista

1. Right-click My Computer, and then click Properties.
2. Right-click My Computer, and then click Properties.
3. Click the Advanced system settings link.
4. Click Environment variables.
5. Click New to add a new system variable name and value.
6. Set the Variable name to ACADCOMPRESSIONMODE
7. Set the Variable value to 1
8. Click OK until you return to the desktop

To Uninstall the WAN Acceleration Hotfix

1. In the product installation folder
2. Delete the acdb17. dll file that you downloaded.
3. Restore the file you renamed to the original name. See To Replace the acdb17.dll File, Step 5.
4. In the Autodesk Shared folder
5. Rename the AcSignCore16.dll file to AcSignCore16.dll.hotfix.
6. Restore the file you renamed to the original name. See To Replace the AcSignCore16.dll File, Step 4.
7. Restart your system.

For more information about this issue, I have previous posts around it
WAN war breaks out over changed file formats in AutoCAD MEP
Reduced write performance for Riverbed WAN links when working with AutoCAD MEP 2007 DWG files
WAN Accelerators Part II