What’s new in vSAN 6.7U3 – SCSI-3 Persistent Reservation

In vSAN 6.7, Windows Server Failover Cluster (WSFC) support was introduced using vSAN iSCSI Service. This support is for physical or virtual WSFC nodes. This feature made it very easy for customers who needed block devices for WSFC clusters that use shared disks. This is a simple feature of enabling vSAN ISCSI service at the cluster level and creating targets/Luns for virtualized VMs.

With vSAN 6.7 Update 3, we have introduced support for SCSI3-PR reservation for WSFC virtualized clusters. Now, there is no need to perform additional configurations to build WSFC using block devices on vSAN Cluster. vSAN disks can be natively used as shared disks or clustered disks for WSFC with SCSI3-PR support.

If customers are using vSAN6.7U3, it is easy for them to choose vSAN native configuration for WSFC than RDM or vSAN ISCSI service. So, as you know in order to build failover cluster we need to share a disk resource between multiple guest VMs. Let’s talk about the basic configuration as how to configure virtual servers for SCSI3-PR support.

I have created two virtual machines WSFC1 and WSFC2 and added SCSI Controller 1 (LSI Logic SAS or VMware Paravirtual). Set SCSI Bus Sharing to physical.

In WSFC1, added two disks 10Gb & 20GB. Use virtual device node as SCSI Controller 1 and disk mode Independent-Persistent.



Now, create the same configuration in WSFC2 and attach the existing virtual disks to the other servers.




One the configuration is completed you may login to virtual server and rescan the storage.


Shared/Clustered vmdks are shown ( Already configured cluster manager role):


vSAN 6.7 U3 and later releases support running WSFC natively by sharing VMDKs through SCSI-3 Persistent Reservations (SCSI3-PR). This is configured in VM configuration only without complicated LUN settings, and there is not needs for pRDMs from legacy storage.

You can also go through reference blog https://bit.ly/2kDgvXn which talks about WSFC with Shared Disks & SCSI-3 Persistent Reservations.

I hope this post will be helpful & informative.


Happy Learning!