Chris Heerschap on 18 Jun 2013 12:12:46 -0700

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Re: [PLUG] FreeNAS vs. Debian for my simple home NAS

I've got quite a bit of experience with FreeNAS in the past six or so months, have done some extensive testing with it, we'll probably use it here at work at some point, but in the meantime I was so impressed with it (and ZFS) that I just set up my own FreeNAS/ZFS server at home.

Some things:

* FreeNAS is wonderfully easy. I had the system out of the box and up and running as an NFS and CIFS server in under an hour.

* ZFS is really, really amazing. Roll mdadm, LVM, and a filesystem all into one, and give you some seriously impressive tools with snapshotting, compression, encryption, and remote replication. (just to name a few) All of this is managed with only two commands, which I've found pretty straightforward considering the capabilities that are provided.

* Yes, ZFS loves RAM if you've got it. I set up my server with 16GB because RAM's pretty cheap. Paid a little more for ECC. It can be used with less. All depends on how much you really need it to do. Have a single-drive system running as a simple NAS in our LAB with 4G of memory.

* Don't bother with ZFS if you can only run 32 bit code.  64 bit only.

* Dedup - don't do it. I can't tell you how much time I've spent with ZFS dedup (because I don't want to think about it) and the conclusion is yes, it works, but the caveats are pretty major, and if you don't have the hardware to support it, you do NOT want to see how slow it can go.

* Yes, ZFS wants no hardware RAID, so it can manage the drives directly.

* ZFS does _NOT_ require RAID or mirroring. You can run it on a single drive just the same way you can run mdadm/LVM/ext4 - and you are in the same boat if that one drive fails. During testing, I've set up an 8 drive stripe - that's zero redundancy, "RAID 0".

* RAID-Z2 is not mirroring. Mirroring is mirroring, RAID-Z2 is the equivalent of RAID-6 (two parity drives). RAIDZ (or Z1) is RAID-5 (single parity), and RAID-Z3 is three parity drives, I don't think there's an equivalent in conventional RAID.

* Uncertain about how a ZFS NAS needs "2 boot disks and 8 data disks", that's pretty arbitrary, especially considering FreeNAS runs the OS off of a USB stick which leaves all the drives for storage.

* Yes, you can add SSD for write (ZIL) or read (L2ARC) caching, but it's not required.

* ZFS is not overkill for a single spindle. You can specify copies=2 so that each block is written in two separate locations, (yes, this cuts your available storage in half, just like mirroring) and if one of those copies gets corrupted (bit rot, whatever) the other one is still there. Plus, all the checksumming that ZFS includes makes it quite a bit better than other filesystems for single spindle systems.

* There's no fsck that requires the filesystem to be unmounted - instead, ZFS scrubs can be done while the filesystem is online. (it's actually required to be online)

* I've done some rudimentary work with ZFS on Linux (ZOL) but nothing too advanced. It works, but there are bits of functionality not available yet. In terms of production use, I've heard rumors of folks using it in prod, but so far it's just rumors.

Thanks to the awesomeness that is ZFS, we're actually looking at the Solaris-based stuff (OmniOS, et al) for non-NAS use. Folks who have worked with me before know my opinion of Solaris, and could tell you how impressive ZFS must be if I'm considering running Solaris. :D


On 6/17/13 3:03 PM, Adam Zion wrote:
OK, so I've got my roll-your-own NAS up and running like so:

  * Ancient Dell Dimension (headless after I got everything up and running)
  * Crunchbang Linux (Debian-based)
  * 2 1 TB USB2 drives (amazingly, the ancient Dell has USB2 ports)
  * SAMBA shares on one of the USBs
  * Nighly rsync copies from one drive to the other to make a de facto
    RAID 1

Ain't pretty, and uses a lot more W of electricity than the Raspberry
Pi-based NAS would have, but it works.

My question is: would there be any advantage to using FreeNAS (or
NAS4Free) on this device vs. remaining w/Crunchbang?

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