FIXED: Exchange 2010 SP1/SP2 DAG on VMWare fail over with Veeam

If you have a DAG setup in your Exchange 2010 SP1/SP2 environment and running Veeam as your OS/Application backup solution you will need to make some cluster timeout changes. The reason is that when Veeam takes the snapshot to then do a VSS backup it will cause the databases in the DAG to fail over and cause lots of alerts.

Below is a simple .bat file script that you can run on a mailbox server inside the cluster. You only need to run this once on one server that is part of a dag. Also, do a reboot at the end. You will also notice that I have the default settings REM’d out at the end in case you want to put it all back.

@Echo Off

REM ##############################################################
REM Changes the delay values for an Exchange 2010 DAG cluster
REM ##############################################################

REM ##############################################################
REM RUN THIS ONCE ON A MAILBOX SERVER THAT IS A MEMBER OF THE DAG
REM ##############################################################

REM ##############################################################
REM ****** N E W S E T T I N G S ******
REM ##############################################################

REM Modified for VEEAM backups do to snapshot causing DAG to fail over

cluster.exe /prop SameSubnetDelay=2000:DWORD
cluster.exe /prop CrossSubnetDelay=4000:DWORD
cluster.exe /prop CrossSubnetThreshold=10:DWORD
cluster.exe /prop SameSubnetThreshold=10:DWORD

REM This is to view your settings
cluster.exe /prop

REM ##############################################################
REM ****** D E F A U L T S E T T I N G S ******
REM ##############################################################

REM Modified for VEEAM backups do to snapshot causing DAG to fail over

REM cluster.exe /prop SameSubnetDelay=1000:DWORD
REM cluster.exe /prop CrossSubnetDelay=1000:DWORD
REM cluster.exe /prop CrossSubnetThreshold=5:DWORD
REM cluster.exe /prop SameSubnetThreshold=5:DWORD

REM This is to view your settings
REM cluster.exe /prop