SyncIQ RPO Missed While the DR Target Runs Out of Space
A company replicates 80 TB from an 8-node primary PowerScale cluster to an 8-node DR cluster over a 1 Gbps WAN. The SyncIQ policy is scheduled every 4 hours, and the stated RPO is 1 hour. Recently, the policy fails intermittently with Snapshot not found and Target is full. The DR cluster is 88% used. SnapshotIQ on the source keeps 30 daily and 12 weekly snapshots; target snapshots are not expiring. Monitoring shows source CPU at 40%, target CPU at 85%, and target disk latency at 25 ms during replication. The administrator proposes raising SyncIQ workers from 8 to 32 and deleting all snapshots on the target to free space. The business cannot accept more than 1 hour of data loss, and the WAN cannot be upgraded for six months.
1. Analyze the two SyncIQ errors. What is the relationship between target capacity, snapshot retention, and the Snapshot not found error?
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Target is full is the primary operational failure: the DR cluster is at 88% and SyncIQ snapshots are not expiring, so each replication run consumes additional target space. When the target cannot create or retain the required snapshot, the policy can fail with Snapshot not found or a related snapshot error. The problem is not simply that snapshots exist; it is that retention, capacity, and replication scheduling are mismatched. Check target snapshot expiration policies, locked snapshots, and whether the SyncIQ policy is set to keep too many target snapshots. Deleting all target snapshots may free space temporarily but can break recovery points and does not solve the recurring growth.
2. Evaluate raising SyncIQ workers from 8 to 32 and deleting all target snapshots. Would either change meet the RPO?
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Raising workers increases concurrency, not WAN bandwidth. It can raise target CPU and disk latency, which are already high at 85% CPU and 25 ms, and may make replication less reliable. Deleting all target snapshots is also unsafe because it removes recovery points and may interrupt the policy. Neither change fixes the 4-hour schedule against a 1-hour RPO. At 1 Gbps, theoretical throughput is about 450 GB per hour, and with overhead closer to 360 GB per hour. If the change rate between snapshots exceeds that, a 1-hour RPO is impossible over this WAN. Measure the actual incremental change rate before promising the RPO.
3. Recommend a remediation plan that addresses capacity, RPO, and monitoring without assuming a WAN upgrade.
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First, stop the bleeding: identify and expire only eligible target snapshots, confirm no snapshot is locked, and add capacity to the DR cluster if 88% used cannot absorb the retention. Second, right-size retention: reduce target snapshot count and align source and target policies so snapshots expire. Third, measure the hourly change rate. If it is under roughly 360 GB per hour, schedule SyncIQ hourly and monitor completion. If it is higher, the 1-hour RPO cannot be met at 1 Gbps; negotiate a realistic RPO or prioritize critical datasets. Use SyncIQ rate limiting and off-hours scheduling for the initial copy, and monitor target CPU, disk latency, and snapshot usage in InsightIQ or CloudIQ. Do not rely on more workers to overcome WAN limits.