White Papers

30 Using Dell PS Series Asynchronous Replication | TR1052
5.1.3.1 Space borrowing for replication
Dell PS Series firmware version 8.0 provides the ability for snapshots, local and remote replicas, and
deleted volumes in the Group Volume Recovery Bin to temporarily borrow space beyond the configured
reserves. This feature, called space borrowing, simplifies configuring reserve space, improves space
utilization, and enhances management of snapshots and replica reserves.
While it is possible to enable or disable space borrowing for snapshots, space borrowing for replication is
automatic and cannot be disabled.
Remote replicas can borrow beyond their total replica reserve, but the total amount of configured reserve
space must still fit within the delegated space. If there is insufficient delegated space on the secondary
group, the system requires manual administrative intervention to increase the amount of delegated space.
Also, if the replica reserve for a volume is configured with a very low value, such as the minimum 105%,
the system can potentially require manual administrative intervention to increase the reserve percentage
so that an in-progress replica can continue. In-progress replicas are not eligible to borrow space.
Note: To use space borrowing for replicas, all members in the secondary group must be running Dell PS
Series firmware version 8.0 or later. Space borrowing for snapshots requires Dell PS Series firmware v6.0
or later. For more information on space borrowing, refer to Space Borrowing for Snapshots and Replicas .