OAB generation on a CCR cluster will fail with error 1021

OAB generation on a CCR cluster will fail with error 1021

There was a new bug found that stops the OAB from being generated with a 1021 while being hosted on a cluster server.

The typical setup has been 1 CCR running on windows 2008 and 1 to multiple Client Access Servers running on Windows 2008.

When you try to update OAB on the CAS server it will fail with error code 1021. This is what the application log event looks like:

Log Name: Application
Source: MSExchangeFDS
Date: 6/15/2008 3:16:36 PM
Event ID: 1021
Category: General
Level: Warning
User: N/A
Computer: OAB-Server
Process MSExchangeFDS.exe (PID=1232). Could not find directory \\OAB-Server\ExchangeOAB\238ag23-f2ab-305w-9fc3-52323c7cbab3. This is normal if the directory has never been generated. Otherwise, make sure this directory and share has read permission for the "Exchange Servers" group.

When we check the OAB folder on the Client Access Server it is empty.

What's broken
The under lying problem stems from a missed case in the Windows 2008 clustering code. With Windows 2008 clustering a file share is specific to either the Node name or one of the cluster name objects that it hosts. In this case if the share is shared by the node name it cannot be accessed by the CMS name.

The OAB generation process *will* succeed in generating the OAB on a CCR cluster running on Windows 2008, however it cannot be copied by the CAS therefor clients will not be able to download the OAB and the OAB directory will be empty.

Workaround until the fix is out
The workaround for now is to manually copy the OAB files to the CAS server file share so clients can access them. This is the same thing that FDS will do when it received a DS Status Notification that the OAB has been generated.