Confirm the relationship state
Start by reviewing the SnapMirror relationship, health, transfer state, lag time, and last transfer error. Determine whether the problem is isolated to one relationship or common to multiple destinations.
Validate intercluster connectivity
Confirm the source and destination clusters can communicate over the intended intercluster LIFs and routes. Review recent network, firewall, routing, DNS, or interface changes before changing the SnapMirror configuration itself.
Check destination capacity and volume state
A healthy network does not guarantee a successful transfer. Confirm destination volume state, aggregate or tier capacity, snapshot-related constraints, and that the relationship configuration still matches the intended protection design.
Use logs and timestamps to correlate the failure
Correlate the last transfer error with EMS events and changes made around the same time. A precise timestamp often turns a generic replication symptom into a specific network, capacity, authentication, or configuration problem.
Avoid destructive recovery shortcuts
Do not break, resync, or recreate a relationship until you understand which copy contains the data you need and the implications for snapshots and recovery. For production systems, document the recovery sequence and rollback plan first.
This article is a general troubleshooting framework. Validate commands and procedures against your platform version, vendor documentation, support requirements, and change-control process before making production changes.