G'day Janaka, Disclaimer that our case was not identical to yours, but maybe you'll find this information useful: I went through a similar process recently - our cinder backend is ceph-rbd, rather than iscsi, but the limitation we ran into was that the ISCSI drive for virtio-scsi block driver does not support SCSI-3 PR, which is required for WFC to work/allow it to be set up/detected as a "valid" disk type. We were technically able to work around the disk-type issue and mount the device as a multipath lun, but due to the virtio driver not supporting SCSI-3 PR, we were not able to proceed further. There is a virtio-scsi driver for paravirtualised devices in KVM, but I do not believe it ships default Openstack. I have not yet found an open bug or patch or discussion about this, nor I have not gotten a POC working, but if you are keen to pursue it, there is an oracle blog about getting virtio-scsi working with persistent reservation in QEMU, and getting that working for WFC, which you might be able to apply that learning to your Openstack. https://blogs.oracle.com/linux/post/configuring-windows-failover-cluster-for... Kind Regards, Joel McLean – Micron21 Pty Ltd -----Original Message----- From: Janaka Wickramasinghe <janakawicks@gmail.com> Sent: Monday, 16 June 2025 1:36 PM To: openstack-discuss@lists.openstack.org Subject: [nova] Is It Possible to Attach a Cinder Volume as device='lun' ? Hi, I'm running an OpenStack setup with Fibre Channel (FC) storage using Cinder volumes. I'm currently trying to configure a Windows Failover Cluster in guest VMs and have encountered an issue. Windows is querying the SCSI device for the Device Identification VPD (Page 0x83). The LUN is attached as a SCSI device using a virtio-scsi controller. In the domain XML (via libvirt), I see that the disk is defined as <disk type='block' device='disk'> also has a <serial>cinder-vol-uuid</serial> When Page 0x83 is queried, it returns the serial value (i.e., the cinder-vol-uuid), which Windows fails to recognize or accept. However, if I modify the XML to use: <disk type='block' device='lun'> and remove the <serial> tag, the guest is able to retrieve the expected information (I had to stop the compute service and restart the libvirt domain). Unfortunately, any changes made directly to the domain XML do not persist. Is there a supported way to specify device='lun' instead of device='disk' for volumes attached ? Any guidance would be greatly appreciated. Thank you With Best regards, Janaka