Hot-added new hard disk attached to an existing LSI Logic SAS controller cannot be detected in Linux kernel 4.2 or newer

Products

• VMware vSphere ESXi

Issue/Introduction

• When user hot adds a new hard disk and attaches it to an existing LSI Logic SAS controller on a Linux kernel 4.2 or newer VM, the new hot added disk cannot be detected by the Linux guest.
• fdisk –l didn’t list new added disk
• rescan-scsi-bus.sh doesn’t detect new added disk.

Environment

• VMware vSphere ESXi 6.5
• VMware vSphere ESXi 5.5
• VMware vSphere ESXi 5.0
• VMware vSphere ESXi 6.0
• VMware vSphere ESXi 5.1

Cause

This issue is caused due to Linux kernel v4.2 and newer doesn't guarantee ordering of timer events with the same expire time but mptsas driver relies on it. So handlers for two notifications coming within the same time period (jiffy) might be reordered. In result hot add logic will not be completed.

Resolution

This issue is resolved in ESXi 6.5 U2.

Workaround:

1. After hot adding LSI Logic SAS disk, reboot the VM.
2. Hot add new disk along with a new LSI Logic SAS controller, then the new disk can be detected by the guest.

Additional Information

Impact/Risks:
User may not be able to use hot added LSI Logic SAS disk.