Backup mailbox server exchange 2013

[cgeorge]

We have 2 exchange 2013 mailbox servers in Cluster.
I backup those 2 machines with network transport mode.
I Always see the following error in the event log during the backup

Event ID 1177

The Cluster service is shutting down because quorum was lost. This could be due to the loss of network connectivity between some or all nodes in the cluster, or a failover of the witness disk.
Run the Validate a Configuration wizard to check your network configuration. If the condition persists, check for hardware or software errors related to the network adapter. Also check for failures in any other network components to which the node is connected such as hubs, switches, or bridges.

[Vitaliy S.]

I believe you should adjust tolerance settings for shutting down the cluster service. Do you see these events at snapshot commit operations?

[Yanish]

We had this issue aswell.
The release of the VMware snapshots causes the VM to lose connectivity for a couple of seconds and results sometimes in a cluster failover.
As Vitaliy mentioned you can play with tollerance settings of exchange DAG as shown here - http://kevingreeneitblog.blogspot.co.il ... lover.html