Should DFS be used for wwwroot synchronization?

Question

I am wondering if to use DFS to synchronize content through a web farm? Does anyone have any experience? We used Robocopy in the past, but found it to be a little spotty and clumsy. Essentially, we want to avoid the need to make ten changes to the content each time a single file changes (this happens very often because our site is outdated and classifies the classic ASP.)

From what I collect, DFS is usually intended for geographically separated locations and is used to make UNC resources easier for users and simplify management.

What I would like to achieve is only to copy content changes to one of ten servers, which will be the center. Then I configured the other nine servers as spokes using FRS.

Any thoughts on this methodology or suggestions for better settings would be greatly appreciated.

Answer 1

For performance reasons, do not point the website to a UNC path. SMB file access is terribly inefficient and slow compared to almost any other way to access files.

You can use DFS-R (through Windows 2003 R2) to enable replication between DFS-enabled public domains, but definitely configure IIS to point to a shared local path, not to UNC.

Answer 2

If you use Win2003, be sure to install R2, DFS replication will improve significantly and does not use FRS. It will do what you want, even on the local network.

Answer 3

Do not use FRS for this, it may get confused. Using DFS and other synchronization technology, such as Symantec Replication Exec , works great. Make sure you create the correct site structure with IP ranges in Active Directoy so that DFS selects the correct servers.

I tried a few years ago with FRS when Windows 2003 was new (before SP1, since then things have gotten better, but I'm not sure). FRS twice completely went crazy and deleted our files, so as not to talk about how many times it just got jammed and failed to recover itself. FRS also only executes synchronized files that are closed, files that remain open are not synchronized (for example, when collecting a collection of log files). FRS is good in environments where you have a moderate amount of relatively small files with not too many changes happening on the server.

Answer 4

I recently disabled UNC DFS as the root of a site on a server; under heavy load the site will not respond to requests. Pointing the wwwroot site to a local drive and restarting IIS quickly restored site speed. I have to recommend that if you go along the DFS route, just ask it to replicate to the local drive instead of using the UNC path as wwwroot.