How to speed up PW file transfer with DFT (Delta File Transfer)

Overview

Starting in the initial v8i release (8.11.5.x), ProjectWise implemented the use of Delta File Transfer (DFT) technology.  This allows for only the differences in the file to have to be transferred as opposed to the entire file, which can significantly improve the user experience when transferring multiple large files over a WAN.  This post is going to explain when it works best, and what settings are needed to take advantage of this feature.  For the most part the settings are turned on by default, but they are listed here for reference.

DFT is used with any file transfer where there is a file located on each end, for example:

• PW Explorer <-> PW Gateway with caching enabled
• PW Explorer <-> PW Caching Server (storage area)
• PW Web Server <-> PW Caching Server (but not from PW Web Client<-> PW Web Server)

Benchmark tool

To determine if DFT is worth using in your environment, a benchmark tool has been provided on machines with the PW Administrator installed. 

The tool (dftbmwiz.exe) can be found in  ..\Program Files(x86)\Bentley\ProjectWise\bin

Once the wizard is started, you will be prompted to log into a datasource.  Be sure to log in with a user that has DFT enabled (with settings outlined below), as well as the setting “allow user to change client/server network settings”, create/delete/free/modify document and create/delete/modify folder.

The wizard will run a test to a specified storage area for three different size files and provide results for checkout/checkin performance with DFT enabled and disabled.  You may find that if the storage area is local, especially for smaller files, the work that DFT is doing could actually take longer than simply transferring the entire file.

Settings

First of all, you need to make sure your datasource is configured to use DFT.  In PW administrator, datasource properties-settings tab.  Under the Network section, check “Enable Delta File Transfer”

Optionally, this can be set in the dmskrnl.cfg file on the Integration server.  In doing so, you have the ability to allow/deny the feature based on an access control list.

;
-----------------------------------------------------------; Section provides Delta File Transfer configuration;
----------------------------------------------------------- [DFT]; This section is used to configure the Delta File Transfer mechanism. By default this feature; is enabled.  The feature can be disabled by setting enabled=false.;; An Access Control List (ACL) may be applied to these entries, to; allow and/or deny access to individual or entire subnets of IP addresses. See the; discussion of ACL attributes at the top of this file for more information. ;Format;enabled=true [ALLOW(ip_address1,ip_address2,...),DENY(ip_address3,ip_address4,...)] ;Examples;enabled=true [ALLOW(193.25.4.*),DENY(10.*.*.*,193.25.*.*)]

Once it’s enabled at the datasource level, you can enable/disable at the user level.  In PW administrator, go to the properties-settings tab of a user and again under the network section; check “Enable Delta File Transfer.” Note that if the datasource level option is turned off, you will not see the option at the user level.

Since DFT requires a copy of the file on both ends of the transfer in order to make the comparison, the users also need the following settings turned on to ensure there will be an existing file in the local working directory.  This also means that DFT would not come into play the first time a user opens a file since there would not yet be a copy on the users machine.

Under the document section of the user settings:

• “leave local copy on check in”
• “leave local copy on free” (optional)
• “use up to date local copy on check out”
• “use up to date local copy on copy out”

Some related BE Communities forum posts

"V8i (SS1) Caching servers DFT with Riverbed like solutions"

http://communities.bentley.com/products/projectwise/content_management/f/342986/t/58655.aspx

"Fetch Files and DFT"

http://communities.bentley.com/products/projectwise/content_management/f/342986/p/57084/134865.aspx#134865

"No DFT for Rasters?"

http://communities.bentley.com/products/projectwise/content_management/f/342986/p/23631/78841.aspx#78841

"Does DFT (Delta File Transfer) work in both directions?"

http://communities.bentley.com/products/projectwise/content_management/f/342986/p/22989/51762.aspx#51762