Windows Server 2019 – Storage Replica asynchronous RPO spikes during backup windows – Fix & Prevention

📖 ~1 min read

Table of contents

1. Symptom & Impact
2. Environment & Reproduction
3. Root Cause Analysis
4. Quick Triage
5. Step-by-Step Diagnosis
6. Solution – Primary Fix
7. Solution – Alternative Approaches
8. Verification & Acceptance Criteria
9. Rollback Plan
10. Prevention & Hardening
11. Related Errors & Cross-Refs
12. References & Further Reading

Symptom & Impact

Asynchronous replication delay increases beyond policy during nightly jobs.

Environment & Reproduction

Reproduced when backup I/O competes with SR transport bandwidth.

Get-SRStatistics
Get-Counter 'Network Interface(*)Bytes Total/sec'

Root Cause Analysis

Backup and replication contend for disk and network resources, increasing queue age.

Quick Triage

Measure RPO trend and identify exact overlap with backup phases.

Get-SRPartnership | Select ReplicationMode,NumOfBytesRemaining
Get-WinEvent -LogName Microsoft-Windows-StorageReplica/Admin -MaxEvents 100

Step-by-Step Diagnosis

Correlate backup schedule, write bursts, and queue growth metrics.

Get-ScheduledTask | ? {$_.TaskName -match 'backup'}
Get-Counter 'LogicalDisk(*)Disk Transfers/sec'

Solution – Primary Fix

Stagger backup jobs and apply SR bandwidth governance for peak windows.

Set-SRPartnership -SourceComputerName  -SourceRGName  -DestinationComputerName  -DestinationRGName  -NewLogSizeInBytes 64GB

Solution – Alternative Approaches

Use separate replication network path to isolate SR from backup traffic.

Verification & Acceptance Criteria

RPO remains within agreed threshold across consecutive backup cycles.

Rollback Plan

Revert schedule and SR tuning changes if application performance regresses.

Prevention & Hardening

Integrate SR RPO dashboards with backup orchestration alerts.

Related Errors & Cross-Refs

Frequently linked with backup target throttling and WAN QoS misclassification.

Related tutorial: View the step-by-step tutorial for Windows Server 2019.

View all Windows Server 2019 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Microsoft Learn: asynchronous Storage Replica monitoring and optimization.