When you use an ESXi system in conjunction with a SAN, you must decide whether file-based tools are more suitable for your particular situation.
When you consider a file-based solution that uses VMware tools and VMFS instead of the array tools, be aware of the following points:
Using VMware tools and VMFS is better for provisioning. One large LUN is allocated and multiple .vmdk files can be placed on that LUN. With an RDM, a new LUN is required for each virtual machine.
Snapshotting is included with your ESXi host at no extra cost.
Using VMFS is easier for ESXi administrators.
ESXi administrators who use the file-based solution are more independent from the SAN administrator.