You can use 2nd generation or above SATA drives in a Sun X4100 or any other server with a SAS bus. Because the X4100 uses a SAS bus it will accept these drives and the connectors are compatible so all you have to do is replace the existing drive (if any) with the SATA drive by placing it in the disk caddy and inserting into an available slot on the front of the X4100. Personally I have tried it and used a Kingston SSD as a boot drive on an X4100.
Important Note: You can connect a SATA drive to the SAS bus but you cannot connect a SAS drive to the SATA bus.
-- Thiers Family -- 
I tried this with an OCZ Octane SATA 2.0 SSD (64G) and it wasn’t having any of it. The LSI controller sees that there’s something there, but refuses to treat it as a disk and allow the OS (Debian Squeeze) to partition etc. Any ideas? This is a second generation SSD I believe?
Can you post the modal number of the Kingston SSD you used that worked. I have a stack of X4100s and wanted to set them all up with SSDs!
John
Hi John,
I used the Kingston SSD NOW 100 V+.
Many thanks – I shall try with one of those then!