Storage performance degradation and SCSI aborts on RDM LUNs with Emulex Fibre Channel adapters(VMware ESXi 8.x)

Products

• VMware vCenter Server

Issue/Introduction

Systemic storage performance degradation, SCSI command aborts, and stall patterns in applications such as backup jobs occur when running RDM (Raw Device Mapping) disks on VMware ESXi hosts with Emulex Fibre Channel adapters. These issues often stem from driver/firmware configuration mismatches between the host adapter and the ESXi hypervisor, leading to severe I/O processing errors.

Symptoms

• ScsiDeviceIO performance deterioration warnings appear in vmkwarning logs.
• Systemic I/O latency spikes (e.g., 600µs to 18ms).
• Active command failures recorded on RDM-mapped LUNs.
• Application-level stalls or timeouts (e.g., backup jobs) occurring immediately upon driver-level aborts.

Environment

• VMware ESXi 8.0 U3
• HPE SN1610E 32Gb FC HBA
• Emulex lpfc driver

Cause

An HBA firmware and driver stack mismatch exists. Running uncertified Emulex lpfc stacks in ESXi 8.x environments causes driver worker threads to become overwhelmed during I/O processing (a condition known as "XRI Starvation"), leading to mailbox timeouts and host-wide I/O stuck notifications. RDM configuration exacerbates this by exposing the Guest OS directly to these driver-level aborts, which bypass the typical VMFS buffering layer.

Resolution

1. Verify HCL compliance: Consult the Broadcom Compatibility Guide to confirm your specific HBA model and ESXi build version are certified for your environment.
2. Perform a coordinated update of the HBA firmware and driver stack to the certified versions (e.g., Firmware 14.4.473.14 and Driver 14.4.0.42-35vmw for ESXi 8.0 U3).
3. Ensure the lpfc driver is at version 14.4.576.11 or higher, as this version includes critical fixes for thread deadlock issues.
4. Monitor vmkwarning logs post-update to confirm the cessation of latency spikes and command failures.

Additional Information

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