Changing connectivity protocol from the storage

Products

• VMware vSphere ESXi

Issue/Introduction

Symptom:

• Changing the storage protocol like NVMe/TCP to iSCSI without unmounting or unmapping the existing LUN to the host results in accessibility issues.

Environment

VMware vSphere ESXi

Resolution

Note: It is not possible to change the storage connectivity protocol without taking downtime.

Steps to change the storage protocol from NVMe/TCP to iSCSI -

• Before the protocol change (Decommissioning NVMe/TCP)

1. 1. Maintenance - Power down all VMs on the datastores being migrated.

   2. Unmount Datastores - Unmount the target VMFS datastores from all 9 hosts.

   3. Detach Devices - Ensure the NVMe devices are detached and then unmap the LUNs from the storage side.
      Refer - Detach a LUN device from ESXi hosts

   4. Remove Configuration - Remove the NVMe/TCP adapter configuration (e.g., discovery controllers) from the ESXi hosts. This ensures they do not try to rediscover the old paths.

 

• After the Switch (Configuring iSCSI)

After storage vendor has confirmed the LUNs are now presented via iSCSI, you must configure iSCSI on every host:

1. 1. Enable iSCSI Adapter - Enable the software iSCSI adapter (vmhba).
      Refer - Add or Remove the Software iSCSI Adapter

   2. Network Configuration - You must have VMkernel ports (e.g., vmk1, vmk2) configured for iSCSI traffic. These ports must be on the correct VLANs and subnets to reach the PowerStore's iSCSI target portals.

   3. Configure Discovery - Add the Dell PowerStore's iSCSI target IP addresses to the "Dynamic Discovery" / "Send Targets" section of the iSCSI adapter.

   4. Rescan HBA - Perform a full rescan of the storage adapter on all hosts. The new iSCSI LUNs should appear.

   5. Verify & Mount - The LUNs should be detected, and because they contain an existing VMFS signature, they should be automatically mounted or be available to "Mount" (do not "format" or "resignature" them).

Additional Information

Accessing the same storage through different transport protocols, such as iSCSI and Fibre Channel is unsupported