Storage Replication Cost Calculator (Cross-Region Copy Pricing)

How to get your inputs

• Inputs: use billing exports, metrics, or logs to get real counts/GB where possible.
• Units: convert throughput (Mbps) or rates (RPS) into monthly units when needed.
• Scenarios: build a baseline and a high-usage scenario to avoid under-budgeting.

Result interpretation

• Replication cost scales with changed data, not total stored GB.
• If replication spikes during backfills or migrations, model a peak month separately.

Common mistakes

• Using a single average and ignoring peak/incident scenarios.
• Double-counting or missing adjacent line items (transfer, logs, retries).

Scenario planning

Validate after changes

• Compare your estimate to the first real bill and adjust assumptions.
• Track the primary driver metric (requests/GB/count) over time.
• Separate one-time backfill costs from ongoing replication to avoid distorted monthly baselines.

Replication intent matrix

• DR readiness: steady changed GB with occasional test-failover spikes.
• Migration: short-lived, very high replicated GB and transfer bursts.
• Multi-region reads: steady replication plus possible egress from secondary reads.
• Compliance archive: low change rate but long retention and storage growth.

Billing boundary checklist

• Replication transfer fee and replica storage fee are modeled separately.
• One-time backfill is not merged into steady monthly change volume.
• Request amplification from replication is captured for high-write workloads.
• Directionality (source to destination) matches provider billing rules.

Common failure patterns

• Using total dataset size instead of changed data volume.
• Missing replica-region storage growth after policy changes.
• Treating DR drill traffic as a normal-month baseline.
• Ignoring write amplification from retries or small object churn.

Next steps