If you try to write data to such a vmdk from the guest operating system (for example, creating a folder), then this data (folder) will be visible only on the host that created it.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 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. This feature is called Multi-writer VMDK. However, there is a VMware technology that allows sharing VMFS-backed disks between several VMs. This prevent 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.
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