ActiveDR Bandwidth Sizing: ActiveDR is a continuous, asynchronous replication technology designed to provide near-zero RPO. Because it streams data continuously rather than in discrete snapshot intervals, the bandwidth between the source and target arrays must be able to handle the application's write workload.

Handling Write Bursts: Application workloads are rarely flat; they have peaks and valleys. If you size the bandwidth exactly to the average change rate, any burst in write activity will cause the replication lag to increase, thereby increasing your RPO.

The 30% Rule: Pure Storage best practices and sizing guides recommend providing a 30% buffer (headroom) above the measured average write rate. This extra capacity ensures that during a high-IO period, the replication engine has enough 'pipe' to catch up quickly and return to a near-sync state.

Calculation Example: If a workload generates an average of 100 MB/s of new unique data, the administrator should ensure at least 130 MB/s of usable, dedicated bandwidth is available between the sites.

Consequences of Under-sizing: If only 10% (Option A) is used, the array may struggle to recover from even minor bursts, leading to a consistently climbing RPO. 50% (Option B) is often considered safe but can be cost-prohibitive or overkill for standard networking budgets unless the workload is exceptionally volatile.