[lug] NAS - OpenNAS, FreeNAS, NAS4Free, or COTS?

Dan Ferris dan at usrsbin.com
Fri Dec 5 21:31:04 MST 2014

I can't speak to the others, but I can tell you about FreeNAS because I 
use it at home and I have extensive FreeBSD experience.

FreeNAS is basically an extremely nice GUI written around FreeBSD and 
ZFS.  FreeNAS is completely about ZFS and there is no point in using the 
legacy UFS volumes.  In fact, I think the next major version is going to 
completely drop the old UFS volumes and go ZFS only.

So with that said:

- FreeNAS requires at least 8 GB of memory to work.  16 GB is better.  
32 GB is best.  If you want to use the deduplication features, you will 
need even more.  You HAVE to use ECC memory with ZFS.  If you do not use 
ECC memory, you risk data corruption.  The FreeNAS forum is full of sob 
stories of people who didn't believe they needed ECC memory and were 
proven wrong.

- ZFS HATES hardware RAID.  You absolutely do not want to use ZFS with 
hardware RAID controllers if you can avoid them.  The controllers hide 
things from ZFS that it likes and the hardware write back cache will 
also screw with it.  Plain old SATA drives connected to the motherboard 
are best.  If you can't avoid hardware RAID, then disable the write back 
cache and use JBOD.  On some LSI controllers, I just make each disk its 
own RAID 0 and disable the write back cache.

- To really get good performance out of ZFS, you will probably want SSDs 
to use as cache.  You will want both a cached ZIL and a cached L2ARC.  I 
use 240GB Intel SSDs and they are serious overkill.  You could probably 
get away with 128 GB or less.

- FreeNAS is fast.  I get around 1 GB / second sequential write speeds 
with 4 plain SATA drives.  I can saturate a gigabit ethernet link with NFS.

- FreeNAS is not the cheapest option.  To get the best performance a 
minimal configuration will probably run you around $1300.  However, 
FreeNAS will blow any other open source NAS out of the water.  It also 
blows away all of the other commercial consumer / prosumer grade NAS 
boxes that I've used.

- The ZFS RAID is much better than normal RAID.  ZFS eliminates all of 
the problems with RAID 5 except for multiple simultaneous drive failures.

My recommended configuration for FreeNAS is:

- Intel C2550 quad core Atom motherboard.  The Asrock C2550-D4I is the 
board I have.
- 16 GB of ECC memory.
- At least 4 drives.  I have 7200 RPM NAS rated Hitachi SATA drives.
- 2 SSDs, one for ZIL and one for L2ARC.  I'd use a good MLC drive like 
the Samsung 840 Pro.  You don't have to have the SSDs, but they make a 
big difference if you have a heavier load.
- A case with hot swap drive bays.


On 12/5/14, 8:26 PM, Jed S. Baer wrote:
> Hi Folks.
> The boss has decided to look at getting a NAS box, primarily for use as a
> target for backups. I'll probably use some sort of rsync-ish or rdiff-ish
> software to do the backups, but that's not a big deal.
> I don't have a specific budget number, but it isn't going to be high-end
> enterprise-class stuff. More like low-mid 2-bay SOHO.
> Unless I'm wrong about budget, this will be a RAID-1 config. If it ends
> up being a 4-bay, then RAID10 (1+0) is likely. Not sure about the RAID
> part, as I'm reading that RAID5 can be problematic, and who knows about
> various vendor-specific RAID extensions? Hey, I'm not a big SA type.
> Needs to have a simple web-based interface, so the boss can manage it if
> I'm not around. This isn't going to be a complex setup anyway. Probably
> just 1 big share. But there is a requirement for some data protection,
> e.g. for the accounting files.
> Data volume requirement is pretty low. Small company. I'd be shocked if
> 1TB wasn't good for several years.
> 1 possibility is to convert one of our old PCs to a NAS box. These are
> *OLD* machines. Would need to get a SATA controller. I'd do an SSD as a
> boot device, and a couple 1TB or 2TB drives. This is my least favorite
> option, because as much I might enjoy fiddling with it, I'm just the IT
> guy there by default -- it isn't my formal job.
> Or, just get a COTS machine. Lots of choices here, so any particular
> thoughts? Thecus, Synology, Qnap, other? Initially, looking around, and
> reading reviews, I think I want to avoid Buffalo.
> TIA for any advice.
> jed
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