

Hot-extend is currently supported only for VMFS flat virtual disks without snapshots opened in persistent mode)

vMotion is only supported for Oracle RAC cluster with up to 8 ESXi hosts You can migrate between ESXi hosts only powered off virtual. You won’t be able to perform the online migration of running VMs with shared disk to another host (vMotion), or datastore (Storage vMotion).The main restrictions of shared VMWare disks in Multi-Writer mode: In most cases, this shared disk operation mode is used in cluster solutions for Oracle RAC and Microsoft MSCS (Microsoft Cluster Service) clusters. Virtual disks, which must be available simultaneously in several VMWare virtual machines, use the Multi-writer technology (available starting from VMware ESXI 5.5 and newer). Multi-writer is also used for VMWare Fault Tolerance when primary and standby virtual machines access a shared vmdk file simultaneously. The Multi-Writer option ensures that a guest host clustering application (such as Oracle RAC or Microsoft MSCS) doesn’t cause data loss when accessing from two or more virtual machines (cluster nodes). This feature is called Multi-writer VMDK. However, there is a VMware technology that allows sharing of VMFS-backed disks between several VMs.

This prevents VMs from accessing other virtual machines’ disks and avoid data corruption or loss. vmdk file simultaneously (locks are used). By default, VMFS, NFS datastores, vSAN are not allowing multiple virtual machines to access the same. VMware VMFS is a clustered file system shared between multiple ESXi hosts.
