When you plan how to set up your storage for your ESX/ESXi systems before you format LUNs with VMFS datastores, you must decide on the LUN size and number of LUNs to use. You can experiment using the adaptive scheme.

1

Create a large LUN (RAID 1+0 or RAID 5), with write caching enabled.

2

Build a VMFS on that LUN.

3

Place four or five virtual disks on the VMFS.

4

Run the applications to determine whether disk performance is acceptable.

If performance is acceptable, you can place additional virtual disks on the VMFS. If performance is not acceptable, create a new, larger LUN, possibly with a different RAID level, and repeat the process. Use migration so that you do not lose virtual machines when you recreate the LUN.