[Gllug] Cheapish NAS.

Tue Feb 16 18:22:35 UTC 2010

On Tue, Feb 16, 2010 at 4:01 AM, general_email at technicalbloke.com
<general_email at technicalbloke.com> wrote:
> Hi All,
>
> I could do with a bit of advice, it seems I have an embarrassment of
> options to choose from! The question is what would be the best
> replacement for my client's ancient win2K file server. They are an
> architects office with ~6 PCs on Gb Ethernet. Many files are quite large
> so throughput fairly important. Budget is ~£450 (pre VAT) for hardware
> and they want at least 1.5Tb of usable space in it. Expandability is
> desirable (naturally) but not pivotal.
>
> I can think of 3 options / strategies so far...
>
> Option 1 - Little NAS boxen like the 2nd gen Drobo+Droboshare and the
> Qnap TS-419P Turbo NAS. My first concerns with those are the throughput
> though. Does anyone own/use one of these things (over Gigabit LAN), if
> so what kind of performance are you seeing? I've head tale of 4 drive
> Drobos only kicking out 12MB/s (bleugh!? Can that be true?).

Closed box, if it breaks you can't do anything about it, so most
likely it is unmaintainable. I would avoid it.

>
> My other concern is the difficulty of data recovery should they fail.
> I'm guessing it's the same situ as a hardware raid controller popping:
> only the exact same model is going to get you your data back (so unless
> you keep a spare handy a failure could mean serious downtime). Are there
> any NAS boxen who's contents you can recover by directly attaching them
> to a PC or do they all work like this? If that's the case then I suppose
> (though I'd REALLY love to avoid the hassle of it) I could build them...

No idea, perhaps because these boxes will never see the interior of a
real data centre :-)

>
> Option 2. A small PC based server with a 3 disk software RAID 5,
> possibly running FreeNAS or OpenFiler. Given that I don't really want
> the hassle I'd want to charge at least £100 for my time building &
> testing the thing. That would leave ~£350 for all the bits. Does that
> seem realistic for a box with reasonable performance (say avg 40MB/s
> throughput)?

I will not even try to address the throughput, I have never had to
care much about it, normally what has been provided to me has been
good enough (performance was not an issue, security and availability
were), in any case, £350 sounds awfully little, that would be aiming
for one of the most basic machines you can find, so most likely the
quality of the components will be on the lacking side of things. If on
top of that you put RAID5 (which is notoriously inefficient for
writes) then you are asking for trouble.

Disks are so cheap that for this solution I would buy  2 as big as
affordable and do a mirror, avoiding the performance penalty of RAID5.

I don't know how much you charge per hour or day, but £100 to set up
such a thing seems awfully little to me.

> I've never built a raid based system before, how much more
> to recovering is there than just slinging all the drives in a fresh box
> and hitting the power switch if, say, the mobo suddenly died? Pls bear
> in mind I'm no linux ninja, almost all my work is supporting Windows &
> Mac at the domestic level and I just switched my workshop machine to
> Ubuntu a mere 18 months ago!

Uhm. You don't do that (I don't even know if it is possible). You redo
your RAID5 volume and recover from archival or backups. Much faster in
general terms.

>
> The third option I can see is to go for a cheap 2 * 1 Tb NAS enclosure
> (~£250), set it to RAID 0 (for high performance) and use the balance of
> the money to make sure it gets very well backed up every day*. I was
> thinking a salvaged p4 box (they have a couple spare) w/ a 2Tb disk &
> open solaris so I could use ZFS and do an rsync + snapshots every few
> hours? Of course I've never setup a business grade backup system either,
> does the above sound like a even half sane plan?

You are really stretching it there, I am not sure if a P4 has the CPU
juice to run OpenSolaris+ZFS (gut feeling says no)..

A Solaris or OpenSolaris would do an excellent sync machine: you rsync
your main machine to your Solaris server and take a snapshot once the
sync is in place. If you need to recover your main machine then you
can refer to your snapshots in Solaris.

In ZFS you can unplug the disks and plug them back with abandon and
the filesystem will be recognized automatically, this is not so easy
with any other volume manager/file system configuration (check YouTube
for examples of this).

So actually, why don't you put as much money as you can on the
hardware, install OpenSolaris on top, and use ZFS's capabilities (I
think the latest version of ZFS supports sharing using CIFS, which
makes it ideal for Windows networks).

In one London OpenSolaris User Group meeting a few months ago I saw a
solution for backups using Solaris/ZFS snapshots to do quick archival
which could be backed up later as time allowed. I think I would prefer
to do something along these lines.

> I'm eager to know what you would do. All advice warmly welcomed, even if
> it's "your budget isn't big enough!". I have to say I'm very tempted by
> Option 1: almost zero maintenance and virtually no time to setup is a
> big win IMHO but I'd rather recommend the right thing than satiate my
> laziness! ;)

Context is king. Most of those self contained boxes are not really
enterprise ready, so all really depends on the tolerance of your
client to outages. After many years of neglect Solaris in x86 is
really enterprise ready (too late for poor Sun) and OpenSolaris seems
to be quite a capable option as well, where you get the cutting edge
goodies. Your problem here would be to ensure your hardware is
supported, but administration of such a box is a good half way
compromise between a hands off, self contained box and a solution
based on older volume managers/file systems.

As much as I would like to say that Linux could work here I am pretty
favourable to the Solaris solution, the only major caveat being what
Oracle's intentions are regarding the Solaris OSes.

>
> Cheers,
>
> Roger.
>
>
> * i.e. Better than their current backup regime. I know the other options
> ought to be "very well backed up" too but I haven't got round to talking
> backup with him yet, he currently just plugs in one of two USB HD's in
> every other day and seems fairly happy doing that. I think using RAID 0
> for the main server would mandate a more serious, regular, automated
> backup system!
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