Fractional space reservation policies enable you to monitor overwrite reserve utilization on fractional space-reserved volumes that contain your Exchange data.
If you store Exchange data on LUNs in a fractional space-reserved volume in a SnapManager environment, you need to avoid an out-of-space condition on the volume such that you have explicit or implicit Exchange-aware control over the deletion of Exchange backup set components.
To address this need, SnapManager provides its own space management tool for monitoring overwrite reserve utilization on the volumes. If overwrite reserve space runs low for a fractional space-reserved volume, SnapManager can take action to prevent the overwrite reserve from becoming fully depleted.
Fractional space reservation policies include specific thresholds that act as trigger points. SnapManager can delete Exchange backup sets or unmount Exchange databases (or both) when the overwrite reserve utilization for the volume reaches the trigger point.