I have a bunch of WD RE4 disks I got from a place that I worked. The drives are 3Gbps SATA II interface. I was going to use them in a server I am building for myself to act as a NAS / SAN for my network. My plan was to run ZFS as the file system using some support method such as FreeNAS, Nexenta, or ZFS on Linux but I am not sure yet.
A question that came to mind today was whether or not the SATA II interface on the drives would actually impact the performance of ZFS negatively. I don't know a ton about ZFS but I do know ZFS uses RAM or other means to cache data. But does that change the fact that the drive are running somewhat slower.
Also unless I have this wrong (which I probably do), WD shows that the sustained drive speed from the disk to host is only 138MB/s which puts only about 50% utilization of the SATA II interface.
Here is the specs I am looking at; Link
Could someone please provide some insight on this?