My blog articles so far have to do with User Files Folders and using Folder Redirection to move them to servers. If you are considering doing this in your environment, there is something you should know -- redirecting a database file and then modifying it will corrupt it. This is a current phenomenon that is very easy to reproduce:
- Put a database file in a redirected folder (that has Offline Files enabled by default).
- Modify the database.
- Witness the corruption.
Time for a rant. If ever there was proof that Vista was rushed out the door, this is it. If ever there was proof that there is slow uptake of Vista by enterprise clients, this is it. Let me explain...
Typically when Folder Redirection is used, Offline Files is also used since it is the default configuration. Offline Files maintains a local cached copy of the redirected data files. This ensures maximum reliability and speed but requires that the local cached copy be synchronized with the network copy. Under Windows XP, database files were excluded from the synchronization process due to their likely large size and were forced to remain on the server only. This caused problems for laptop users who counted on the Offline Files feature to give them access to their network files while away from the network. Vista introduces a new feature of Offline Files called "Bitmap Differential Transfer" (BDT). BDT allows Vista to support the synchronization of all file types, including databases, because it does a block-by-block synchronization and it no longer needs to synchronize an entire file every time. Here is one Microsoft site promoting the feature. Here is a blog that discusses the feature as well. The problem is that the feature just doesn't work - at least it didn't work at my client site and Microsoft support easily reproduced it as well. I was able to witness the corruption by simply creating an Access database in a redirected folder and then modifying it by moving a button control on a form. Within minutes I had Access spitting out all sorts of random error messages. In my book, if a new product's "feature" just doesn't work (no strange arrangement of bits required), then it was rushed to market.
Now here's the bit that has shocked me. I found a glaring problem. It was easily reproduced. There has been no mention of it on the internet that I can find. When I got the early release of the patch destined for SP1, I was told by Microsoft that I would be the first client trying it. This was September. How is it possible that the product has been out for eight months and no one is reporting it or receiving support to fix it? I can only surmise that Folder Redirection is being used only by the larger clients who are having trouble with the implementation of Windows Vista - they have yet to deploy the product to users who might think of putting a database in one of the redirected user folders and attempt to modify it.