This KB provides information about vSAN and its supportability for Application Clustering Solutions using native shared VMDKs or vSAN iSCSI Targets.
Solutions are:
Customer investigating the following options:
1. As occurs with VMFS and NFS datastores, VMware vSAN prevents multiple virtual machines from opening the same virtual disk (VMDK) in read-write mode. This is to protect the data stored on the virtual disk from corruption caused by multiple writers on the non-cluster-aware filesystems used by most guest OSes. vSphere has two ways to share vmdks:
Both options remove vSphere locking on the vmdks and the VMs can write at the same time to the same files. Customers must leverage cluster-aware filesystems that have distributed write (multi-writer) capability or else there could be data corruption.
2. Also, VMware vSAN iSCSI targets can be used to provide SCSI-3 locking and LUNs required for a number of clustered applications.
For more information regarding SCSI-3 locking