A DPM server can have a maximum size of %MaxSPReplicaVolumeSize; TB for SharePoint replica volumes. If you exceed this limit, ...

A DPM server can have a maximum size of %MaxSPReplicaVolumeSize; TB for SharePoint replica volumes. If you exceed this limit, the DPM server may miss the backup SLA and eventually it may become unresponsive. You are currently using %SPReplicaVolumeSize; TB of SharePoint replica volume size on %DPMServerName;.