After modifying the iser_LunQDepth parameter in the ESXi host configuration and rebooting the system, the iSER adapter is no longer detected.

Products

• VMware vSphere ESXi

Issue/Introduction

• After modifying the iser_LunQDepth parameter in the ESXi host configuration and rebooting the system, the iSER adapter is no longer detected.
• The iSER adapter may show up as "Unknown" or "Not Available" in the vSphere client.

Environment

VMware vSphere ESXi 7.x
VMware vSphere ESXi 8.x

Cause

The iser_LunQDepth parameter was set to 10 or any value using the following command:

esxcli system module parameters set -m iser -p iser_LunQDepth=10

After rebooting the ESXi host, the iSER adapter was no longer detected. This manifested as the adapter showing "Unknown" or "Not Available" in the vSphere client.
The following alert message appeared in the /var/log/boot.gz file:

ALERT: iser: init_module: Invalid iser_LunQDepth value of 10

The root cause of the issue is the invalid iser_LunQDepth value of 10. This value falls outside the acceptable range for this parameter. The iser_LunQDepth parameter, which controls the number of outstanding I/O requests for iSER, is typically limited to values between 32 and 512.

Resolution

To resolve this problem, please refer to the steps outlined below:

1. SSH to ESXi host using root account 

2. To remove the invalid iser_LunQDepth value, run the following command and then reboot the ESXi host:

esxcfg-module --set-options "" iser

3.  After the reboot, set a valid iser_LunQDepth value, such as 32, using this command followed by another reboot:

esxcli system module parameters set -m iser -p iser_LunQDepth=32

Steps to Validate:

1. Check Adapter Status in vSphere Client:
Log in to the vSphere Client and navigate to the ESXi host where you resolved the issue.
Check the status of the iSER adapter in the host's configuration. It should now show as "Available".

2. Validate iser_LunQDepth Value:
Use the following command on the ESXi host to verify the current iser_LunQDepth value:

esxcli system module parameters get -m iser -p iser_LunQDepth

The output will show the current iser_LunQDepth value. Ensure it matches the value specified in step3.


Note:
Always consult the documentation for your specific hardware components to verify the correct iser_LunQDepth range for your environment.
By validating the adapter status and the iser_LunQDepth value, you can confirm that the issue has been resolved and the iSER protocol is working properly.

Additional Information

If the issue persists after following these steps, contact the storage array vendor or network adapter manufacturer or Broadcom Support for further assistance