[sclug] NAS

Jonathan H N Chin jc254 at newton.cam.ac.uk
Thu Nov 3 16:17:34 UTC 2011

haughtonomous wrote:
> Has anyone built themselves a low-power NAS?

The Synology DS411slim is very nice. 17W fully loaded.
About #230 bare (from ebuyer) so more than you want to pay.
It only takes 2.5" drives (x4). Very very cute though.


I've got the DS411j which takes 3.5" disks but, slightly
surprisingly, has less grunt and costs more (about #275).
Claimed 31W fully loaded. (Mine estimates it will run for
about half an hour off my 700VA UPS).

They can be configured to power up/down automatically
(so mine turns off overnight when I know I'll be in bed)
and you can make the disks spin down when they've been idle
for a while.

If you hang one off a supported UPS, it'll shut down cleanly
if there's an extended power failure and then restart when the
power comes back.

Some factors to consider:

    - size
    - power consumption
        - cost
        - heat, if you're sticking it in a closet
    - noise level
    - managability
    - easy of use
    - maintainability

For a cheap and cheerful build-your-own, I'd definitely recommend ZFS.
It's really really nice to manage. The linux zfs-fuse implementation
has some major shortcomings, but works okay. ZFS is also available in
freebsd and opensolaris, among others. Looks like freenas uses it too.

I use ZFS on my laptop (debian with zfs-fuse).

The internal SSD contains one zfs pool. I have two external USB drives
for backup, containing another pool. They can be used together as a
mirrored pair, or I can leave one in my safe, carry the other around
and do regular backups, and then resynchronise them when I get home.

Resynchronising is very efficient. Unlike an rsync, ZFS is able to
copy only the data that has actually changed (so, for example, moving
files around won't phase it - only the directory metadata will need
to be copied) and it doesn't need to compare file content to locate
changes since they are tracked explicitly.


Jonathan H N Chin

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