Excel and PDF Files disappearing in a DFS Replicated folder

Hi everyone,

We are currently facing an issue in our environment and we can't figure out why this is happening. We have two scenarios under which files are disappearing in one of the DFS Replicated folders that we have in our environment. Here is a breakdown of our environnment:

• We have 4 File Servers Windows Server 2008 R2 Almost Fully Patched (2 Weeks Ago) in Four Different Sites
• The servers will be named as follow in the thread: MTL, AMX, PLT, 155
• All our sites are linked by site-to-site VPN
• We have several DFS Replicated folders but the folder we are currently having problem with is called "Public"
• The "Public" folder in all of our server is published in the DFS Namespace as \\domain.com\Public
• The data is replicating almost instantly on all of our servers
• Our DFS Replication topology is "Hub and Spoke" Our MTL server is the Hub and AMX, PLT and 155 are the spokes
• The site where MTL resides have a 100Mbps/100Mbps Fiber Optic WAN Connection
• The site where PLT resides have a 10Mbps/10Mbps Fiber Optic WAN Connection
• The site where AMX resides have a 10Mbps/10Mbps Fiber Optic WAN Connection
• The site where 155 resides have a 230Mbps/30Mbps Cable WAN Connection
• The maximum latency between our sites is maximum 100 ms
• Our DFS Replication Schedule is from 5AM to 10PM with 8 Mbps Bandwidth Limit
• We also have a file locking mechanism that is present on all the servers called peerlock.
• We have an Anti-Virus installed on the server MTL but the exceptions were added as per the following article: http://support.microsoft.com/kb/822158/

At the moment, we have several issues where file are disappearing. Those are mostly Excel Shared Workbook that are being modified on several servers at the same time. This seems to be cause by having a DFS conflict on multiple servers at the same time (Error 4412) which is causing the file being dropped on the ConflictAndDeleted folder.

Now, since I know I cannot stop the DFSR to put that file in the conflict and deleted folder following a conflict, I would like to know how we can prevent that file disappearing to happen or what are the other alternatives in being able to be able to modify this file multiple users at once.

Here is the Shared Excel file opening process as I understand it:

1. Users open the file using Excel (This creates an Open Handle on the file server and locks the file on all DFS Servers. This being done, no other users can open, save, edit the file)
2. After the file is fully opened on the user's computer, the lock is being removed by Peerlock (Which makes the file available again for opening, editing, saving.
3. When saving the file, an Open handle is created on the server, which makes the file locked for other users (If the file was not locked in the first place).

This process to me seems to be fairly simple and since we have the locking system, we should not have any problems of the file being different on several servers at once. Also, we saw that the error was mostly happening when one of the following was true:

• The file was unshared, modified, then reshared by a user.
• The file contained Links.

We have today disabled the Preview Pane as we saw it might have been the cause of some wrong file locking and file opening.

Thank you very much for your time and for your answers.

Regards,