I'm gathering specs to build a highly reliable file server, somewhat future proof for the next 3-5 years. The component I'm starting with is the motherboard.
Are there motherboards that have been shown to support ECC RAM (and which particular models?) and also USB 3.0? I've read that there are such chipsets with ECC support, but motherboard manufacturers won't guarantee they work, or won't even offer the required BIOS options.
ECC support depends on few things:
As such, with new systems support should be straight-forward, but it's non-existent in consumer grade boards.
On the other hand, workstation and server boards don't usually ship with new chipsets (on which USB 3.0 support is based).
The quickest way to get mainboard with ECC and USB3.0 would be to buy a normal workstation mobo and add USB3.0 PCIe controller.
As a side note: don't use USB for external HDDs, it will eat your CPU cycles like no tommorow. eSATA is faster and with port multiplexers allows to connect multiple drives.
For ECC support, look to Server/Workstation class motherboards. If you plan to use ZFS as a basis for a homegrown fileserver, ECC is very important. USB 3 or even 3.1 can be added using PCIe cards. This can be handy to connect various consumer grade gear. For extending storage, eSATA (optionally with port multiplexing) is a better way to go. Also when you look at motherboard options, the CPU/RAM that best fits your use case can vary considerably. Do you need high throughput for single threaded workloads? Or are you doing parallel workloads needing many threads? How much RAM do you need? What is your price range?
Future proofing a file server will more likely involve how many DIMMs it can support, how many CPUs it can support, the chipset (as Hubert explained), etc. etc. You didn't mention CPUs specifically so if you're looking for a desktop type processor (not Xeon or Opteron), then ECC support will vary and is usually rare for desktop processors.
If you're looking to build a "reliable" file server with desktop parts, odds are ECC support is not going to be an option. What do you specifically intend to do with the file server? Do you think that ECC supported RAM will make it more reliable? Perhaps you can fill us in on what you intend to do and what parts you're specifically thinking of using.
