Forum Discussion
ASHCI cluster with different RAM amounts
been looking through server requirements and things, and i cant see a definitive answer of whether i need to have the same amount of RAM per ASHCI host. i appreciate it may not be best practice due t...
- Azure Stack HCI does not require identical hardware across all nodes, including RAM.
- Cluster-aware updating (CAU) and failover clustering work with mixed RAM configurations, but performance can vary.
- Storage Spaces Direct (S2D) will work, but imbalances in RAM can lead to caching inefficiencies.
2️⃣ Failover Considerations
- If a VM with high RAM allocation fails over to a node with less RAM, it may fail to start due to insufficient memory.
- Using VM Placement Policies (via SCVMM or PowerShell) allows you to set preferred and possible owners to avoid overload.
- Memory overcommitment with dynamic memory is possible, but not ideal for production workloads.
3️⃣ Performance Implications
- Nodes with higher RAM can handle more VMs and better caching.
- Nodes with lower RAM may experience bottlenecks when VMs are distributed unevenly.
- The cluster balancer will attempt to distribute VMs, but manual tuning may be required.
4️⃣ Best Practices if Using Mixed RAM
✅ Use Preferred & Possible Owners: Assign VMs based on available RAM.
✅ Set VM Startup Priorities: Ensure critical VMs start first if failover occurs.
✅ Monitor Memory Usage: Use Windows Admin Center or SCVMM to track cluster health.
✅ Test Failover Scenarios: Ensure VMs can be redistributed without major performance degradation.