Is there any performance loss when connecting a SATA SSD to a SAS controller? Edit: Assume the controller doesn't have SATA connectors and I use a SATA to SAS interposer. Will there be any performance loss to either the SSD or the other drives (I have 2 146GB SAS 15K RPM Drives in RAID 1)
From what to what? you don't say - let's assume you mean will the SSD perform at a lower level than if connected to a SATA controller - if that's the case then I'd suggest not, if the controller supports SATA then it'll act like a SATA controller so you shouldn't see any drop off. If you mean something else then please clarify.
Well, first you have to verify that you can connect the drive at all! Second, this would seem to be a simple math problem- Throughput of the SAS card's bus, divided by number of SSDs on the card / or theoretical bandwidth of each SSD, compared to a similar calculation using the SATA interface.
In terms of software, it's really 100% dependent on what you're running, what drivers you have, and what kind of server setup you have. My suggestion would be to bit the bullet, get a test set of kit, and run a benchmark.