The only valid option to do so if you still want to be able to run some OS X servers on them was to replace the Xserves by Mac Pros.
So we bought two of those black cans. 12 cores.
As our storage is attached via 10g SFP we needed to so the same with our new servers.
So I ordered two 'Promise SANLink2 10G SFP+'.
It was only then when the question arised, whether VMware Sphere with ESXi was going to support this Thunderbolt interface.
So I sent an email to Promise.
They told me that as they only supplied Mac drivers, this was not going to work.
On the other hand, I had this bit of information:
The SANlink2 is based on Intel's 10Gbe chipset likeSo when the interfaces arrived, I tried them out using a MacBook Pro.
our 10Gbe Intel cards do and so it should work
And guess what: It works.
The 'Promise SANLink2 10G SFP+' shows up as a regular 'Intel Corporation 82599EB 10-Gigabit SFI/SFP+ Network Connection' with two interfaces at 10000, just as it should.