We are deploying ASM via ESX VM and would like to know the best practice for the storage layer...
Do we use RDM or VMFS disks?
5.1.1 Virtual Machine File System (VMFS) VMFS is a cluster file system that provides storage virtualization optimized for virtual machines. Each virtual machine is encapsulated in a set of files and VMFS is the default storage system for these files on physical SCSI disks and partitions. VMFS allows multiple ESX/ESXi instances to access shared virtual machine storage concurrently. It also enables virtualization-based distributed infrastructure services such as vMotion, DRS, and VMware HA to operate across a cluster of ESX/ESXi hosts.
5.1.2 Raw Device Mapping VMware also supports Raw Device Mapping (RDM). RDM allows a virtual machine to directly access a volume on the physical storage subsystem, and can be used only with Fibre Channel or iSCSI. RDM can be thought of as providing a symbolic link from a VMFS volume to a raw volume. The mapping makes volumes appear as files in a VMFS volume. The mapping file, not the raw volume, is referenced in the virtual machine configuration.
I would think RDM, but I see that there are liimitations of RDM:
-we can use only virtual mode RDM – as with physical mode vmotion doesn’t work.
-the disk size limit is 2TB for RDM disk.