vsphere-esxi-vcenter-server-55-storage-guide

Chapter 17 Raw Device Mapping10 Select a compatibility mode.OptionPhysicalVirtualDescriptionAllows the guest operating system to access the hardware directly.Physical compatibility is useful if you are using SAN-aware applicationson the virtual machine. However, a virtual machine with a physicalcompatibility RDM cannot be cloned, made into a template, or migrated ifthe migration involves copying the disk.Allows the RDM to behave as if it were a virtual disk, so you can use suchfeatures as taking snapshots, cloning, and so on. When you clone the diskor make a template out of it, the contents of the LUN are copied intoa .vmdk virtual disk file. When you migrate a virtual compatibility modeRDM, you can migrate the mapping file or copy the contents of the LUNinto a virtual disk.11 If you selected virtual compatibility mode, select a disk mode.Disk modes are not available for RDM disks using physical compatibility mode.OptionDependentIndependent - PersistentIndependent - NonpersistentDescriptionDependent disks are included in snapshots.Disks in persistent mode behave like conventional disks on your physicalcomputer. All data written to a disk in persistent mode are writtenpermanently to the disk.Changes to disks in nonpersistent mode are discarded when you power offor reset the virtual machine. With nonpersistent mode, you can restart thevirtual machine with a virtual disk in the same state every time. Changesto the disk are written to and read from a redo log file that is deleted whenyou power off or reset.12 Click OK.Manage Paths for a Mapped LUN in the vSphere Web ClientWhen you use virtual machines with RDMs, you can manage paths for mapped raw LUNs.Procedure1 In the vSphere Web Client, browse to the virtual machine.2 Right-click the virtual machine and select Edit Settings.3 Click the Virtual Hardware tab and click Hard Disk to expand the disk options menu.4 Click Manage Paths.5 Use the Edit Multipathing Policies dialog box to enable or disable paths, set multipathing policy, andspecify the preferred path.For information on managing paths, see Chapter 23, “Understanding Multipathing and Failover,” onpage 215.VMware, Inc. 161