Frequent Power On Reset Unit Attentions occur on path

Products

• VMware vSphere ESXi

Issue/Introduction

ESXi detects repeated PowerOn Reset Unit Attention conditions on the path in the event message in a short period of time. This is not expected behavior and indicates a possible problem with the SAN.

Example:
Messages are displayed which are similar to:

Frequent PowerOn Reset Unit Attentions are occurring on path vmhba0:C1:T0:L0. This may indicate a storage problem. Affected device: naa.###################. Affected datastores:vmdatafiles
cpu0:2659)ScsiCore: 1460: Power-on Reset occurred on vmhba1:C0:T2:L0
cpu7:2055)NMP: nmp_ThrottleLogForDevice:2318: Cmd 0x2a (0x41244038d380, 2056) to dev "naa.###################" on path "vmhba1:C0:T1:L0" Failed: H:0xb D:0x0 P:0x0 Possible sense data: 0x0 0x0 0x0. Act:NONE

Impact:

• The SAN might be heavily congested which can cause I/O requests to take a long time to complete.
• The virtual machine storage performance is degraded.

Environment

VMware vSphere ESXi 7.0
VMware vSphere ESXi 8.0

Cause

The messages are caused by activity on the array outside of the ESXi host's scope.

Resolution

To resolve this issue,

1. Investigate the condition of the storage attached to the ESXi host.
2. As the messages are caused by activity on the array outside of the ESXi host's scope, the storage administrator must use storage-specific tools to isolate the cause of the problem.

Additional Information

• The RDM LUN resets while powering on the virtual machine