Home ZFS based NAS...What processor/chipset to use?

Question

So, I'm building a home/personal NAS. My plan is to expose both SMB fileshares for sharing files/media between hosts, but also to carve an iSCSI target LUN out of it for use by VMWare as a datastore. I want to use ZFS (software RAID) so that means I'll either be using FreeNAS, Solaris Express, or OpenIndiana.

My question is basically: How much horsepower do I need? Obviously I/O is going to be my bottleneck but I want to be sure that I am not limiting my I/O because of a slow processor or chipset.

So far the hardware plan is to use an Intel i3 and motherboard with one of the H87, Q87, or Z87 chipsets, a SAS controller (JBOD, no RAID) and if budget allows, I'm also hoping to get an SSD for the ZFS L2ARC and ZIL.

Does anyone think I could get away with an Intel Atom or cheaper/less-capable processor/chipset than the i3 and [HQZ]87 listed above?

Answer 1

For small-scale NAS amount of memory is more important than CPU power for ZFS, IMHO. Almost any x86 CPU on the market would do the job performance-wise, though some CPUs are better than others.

You do want CPU that supports 64-bit mode. That rules out older Atoms.

I would also recommend investing in a server board that supports ECC memory. ZFS's ability to validate data consistency on the disk if not worth a damn if your memory is bad (and it happens) and causes your OS to write garbage to disk.

i3 (or, even better, xeon e3-12xx v2/v3) should be more than sufficient. If you want to save few bucks, get Pentium G21xx or one of its siblings (and, surprisingly, they do support ECC memory, too) or a celeron that supports ECC.

SSD for L2 ARC is very nice to have, but keep in mind that your RAM needs to scale up with L2 ARC size. Rough rule of thumb is ~ 1GB of RAM for each 10G of L2 ARC. Considering that memory is quite affordable these days, I would go with 8GB as a minimum.

As for SAS controllers, LSI SAS/SATA controllers seem to be well supported by almost everyone, be it Windows, Linux, FreeBSD or solaris variants. You can get rebranded ones pretty cheaply (google "IBM M1015" -- it's rebadged LSI 9220-8i), flash IT firmware and it should serve you well.

That should be more than enough for home use, unless your home network is 10Gbps. :-)

I would not recommend Atoms -- the ones that support 64-bit mode and ECC memory do exist, but you're not very likely to find them in stores.