SAN array is a Clariion CX300 with DPE, DAE, and DAE2.
Currently have two LUNs (two datastores) from FC SCSI disks connected to ESX.
Trying to add two 2TB LUNs (one datastore + one extent) from FC ATA disks to ESX.
Have two ESX hosts attached to the same LUNs/datastores.
ESX lets me add one LUN as datastore ATA_1 and format as VMFS-3. Shows 2TB capacity, 2TB free in both hosts.
ESX lets me add extent to datastore ATA_1 and format as VMFS-3. Shows 4TB capacity, 4TB free in both hosts.
However, after performing a rescan, the extent disappears. Shows 4TB capacity, 2TB free in both hosts.
ESX only cares about the Fibre channel connection and not what disks your SAN uses. So the problem you are seeing is either a presentation or zoning problem and not disk issue with ESX. Your SAN can present any media.
SATA is the only supported ATA disk available for Local storage or shared SCSI storage. SAN, iSCSI, or NFS does not figure into that.
Edward L. Haletky
VMware Communities User Moderator
Author of the book 'VMWare ESX Server in the Enterprise: Planning and Securing Virtualization Servers', Copyright 2008 Pearson Education.
CIO Virtualization Blog: http://www.cio.com/blog/index/topic/168354
As well as the Virtualization Wiki at http://www.astroarch.com/wiki/index.php/Virtualization
The problem you are seeing is with the addition of the extent. I use them as well, and in order to add extents, after the extent has been added, you will need to reboot. I've noticed this when the vmfs you are adding an extent to is shared among multiple hosts. So, create the vmfs, add the extent, and then reboot.
You can try and use fdisk, and vmkfstools to create the partitions. Adding the extent in that way sometimes yields better results, but it's more error prone, and the syntax is a bit kludgy. If you can get the downtime, then adding it through the GUI and rebooting is the easier way.