I've done some searching on this subject and have heard a few different opinions on it so I'm looking for a definitive answer.
I'm building a testing server for VMWare ESX. It will be a combination testbed for web, email, samba, and more.
The server will have a pair of 73GB 15k SCSI drives in RAID 1 to install ESX and the VMs to and we'd like to have a SATA drive for file sharing as well. One of the VMs would mount the SATA drive and share it via Samba.
With the right SATA controller card (LSI MegaRAID, for instance) is this possible?
Yes. If you have a controller listed in Compatibility Guide, dont matter to ESX what disk type you have.
I install ESX3.0.1 on Dell PE840 with a SAS Perc5i and 4 SATA 160G.
Take a look at http://www.vmware.com/vmtn/resources/communitysupport/
You have to differentiate between what works and what is supported.
SATA is not supported according to the HCL to store VMDK files, but it works if your controller masks the SATA disk as a SCSI disk. This is okay for testing purposes but not recommended for production use. One of my test systems is using for example the LSI Logic MegaRAID 150-4.
You may want to read this web site for a list of controllers that mask SATA disks as SCSI.
You might also run into issues that you select a supported controller, but this controller only works if you enable hardware RAID support.