I've been booting ESX 2.5.3 over an FC SAN in my lab and I have a few Windows 2003 virtual machines as well as a RHEL 4.0U2 virtual machine. The upgrade process took me about 30 minutes and was flawless.
Setting up the ESX iSCSI SW initiator was a breeze and after I was done I connected my existing VMs via iSCSI thru the ESX layer. Because there's no multipathing available for iSCSI as there is with Fibre Channel with the 3.0.0 release I used NIC Teaming to accomplish virtually the same thing. The whole process didn't take more than 10-15 minutes.
With the 3.0.0 version of ESX, VMware does not support booting ESX server over iSCSI, however, they do support VM's residing on iSCSI LUNs. Even though you could connect an iSCSI HBA (i.e Qlogic 4010/4050/4052) and boot the ESX server, the status of the iSCSI HBA for this release is deemed "experimental only". Support for the iSCSI HBA should be in the 3.0.1 release. I also hear that iSCSI multipathing support will also be available on this release as well.
So if you have a whole nunch of diskless blades you want to boot over iSCSI with VMware ESX you'll be able to get it done in the 3.0.1 release.
I also noticed that some of the restrictions in terms of suported FC HBAs for SAN booting have been lifted with the 3.0.0 release. For example, you can now use Emulex & Qlogic HBAs whereas before only Qlogic 23xx was supported. Additionally, RDMs (Raw Device Mappings) are now supported in conjuction with SAN booting whereas before they were not.
Further restrictions with regards to SAN booting that have been lifted, also include booting from the lowest number WWN, and lowest number LUN. The restriction that remains is that you can not boot ESX without a Fabric, meaning you can't boot ESX via a direct connection to a disk array. Well, I believe you can it's just that VMware won't support it.
One thing though that I have yet to figure out is why would VMware allow and support an ESX install on internal IDE/ATA drives but not on internal SATA drives. I've tried to install ESX on a server with an Adaptec 1210SA controller and during setup it couldn't find my disk. So it looks like a driver issue. Poking around on the net I found someone who used an LSI MegaRaid 150-2 controller and was successful in installing ESX on a SATA RAID 5 partition.
That made me curious so I spent $20 on Ebay and got an LSI Megaraid 150-2 controller and was successful in installing ESX. Like I said before, this is not supported by VMware which is bizarre but for testing purposes it works just fine.
One thing to watch out for is that:
- VMware does not currently support MSCS with Windows 2003 SP1. SP1 has incorporated some changes that will not allow MSCS to fuction properly with any ESX version at this time. VMware has been working with Microsoft on a resolution but have no ETA for a fix