Because of my bad english, your answer was not what I was expecting. But anyway, it was helpfull and I have some questions :

Netapp recommends starting offset divisible by 4096, is that because their LUN has 4096 chunk size? So if I have another storage solution, example SAS RAID, I should get the stripe size and then my starting offset must be divisible by it?

Also, about partition alignement, I understood the 3 levels that needs to be aligned : vmdk, vmfs, raid stripe size, is this right?

Also, ESX 3 automaticly align new created datastores, but what about the default datastore created uppon installation? Is it aligned?

My case : A server with local raid5 storage (1.5To) that will be used for VM OS virtual disks. And external storage for data.

During the installation of ESXi, I choose use all the local storage for ESXi. Is that storage aligned? Because I don't see 128 as starting offset, BUT, it's divisible by 128 (starting offset is 9922560)

Thanks.