In a Nutanix cluster, I/O latency can be affected by several factors. Given the scenario where a 32-node hybrid cluster is experiencing I/O latency, one possible cause could be the Information Life Cycle Management (ILM) constantly moving data due to curator scans1.

In a Nutanix cluster, ILM is responsible for managing data placement across different storage tiers. It promotes frequently accessed data to higher-performance tiers (like SSDs) and demotes less frequently accessed data to lower-performance tiers (like HDDs)1. This process involves moving data around, which can cause I/O operations to take longer, leading to increased latency1.

If the working set size (WSS) exceeds the SSD tier capacity, ILM will have to constantly move data between the SSD and HDD tiers to accommodate new data. This constant data movement can lead to increased I/O latency1.

Therefore, if curator scans caused by ILM are constantly moving data, it could be the reason for the observed I/O latency in this scenario.

References:

Disk I/O Latency on a Nutanix Cluster | Nutanix Community

Nutanix Volumes - Recommendations And Best Practices

Nutanix Support & Insights

Expand Cluster with Nodes with Higher NIC SPEED (25 GBPS) | Nutanix …

[Scaling Up VM Storage Performance on AHV – Volume Group … - Nutanix]

[About support for Nutanix segmented iSCSI network | Managing AHV …]