Hey, noticed a recurring setup issue during performance reviews: storing VM disk files on the same physical drive/array as the host OS. This might seem harmless initially, but it often becomes a hidden bottleneck as workloads scale.
You’ll typically see both the host and VMs lagging under pressure. Why? Because their I/O operations end up fighting for the same bandwidth and IOPS, causing storage queues to back up. During peak hours, this can even trigger application timeouts.
The fix is simple: isolate those I/O paths.
- Prioritize moving VM disks to dedicated physical drives—NVMe or SAS SSDs are ideal here.
- If using shared storage, assign separate controller channels or HBAs to host OS drives and VM disks.
- For production environments, consider RAID 10 or all-flash arrays to avoid mechanical disk limitations.
Pro tip: Keep an eye on disk latency (aim for ≤5ms) and queue depth. For critical workloads, implement storage QoS. Hyper-converged users can leverage vSAN’s auto-balancing.
Physically separating host and VM disk I/O paths is key to stable performance. If you’ve tackled this in your environment, share your lessons below!
