Hi,
On Sat, Mar 07 at 12:14, Rob Malpass wrote:
> So it got me thinking about an equivalent DIY solution. I already have a few hard drives I could use but I have a few requirements:
> 1) I'd like the drives to be hot swappable like the Drobo
I have to ask why ?
Hotswap adds considerably to the cost of the system and for most domestic
uses it has no big advantage. Half an hours down time while you swap a
faulty drive isn't gonna kill the household.
As a non-hotswap domestic solution the ARTiGO A2000[1] looks good. 250 quid
just add RAM and drives. Only two drives though.
For hot swap the only way to go is SATA these days. The old IDE caddies
never really worked, and SCSI is too expensive. At work we use ICYdock
4 into 3 and 5 into 3 drive bays[2]. You see hot swap has just added 80
quid to your build cost.
Another interesting product for home use might be a mini-server case
with 4 hotswap bays. Chenbro Home Server/NAS Chassis - ES34069[3]
but again you are paying that premium for hotswap.
> 2) Not sure what version of RAID to go for - any adivce?
Two main choices. RAID 1 mirrors two drives, you get speed, security,
it's simple to understand, you get 1/2 the total capacity. (Yes I know
you can mirror more than 2 drives but I'm trying to keep this simple.
See wikipedia for far more detail.)
RAID 5 combines N drives (N>2) to provide (N-1)/N total capacity plus
a parity disk. Any one drive fails it can be rebuilt from the others.
> 3) Presume I'd need a motherboard and case that could handle RAID. I'm very green here - is RAID a software thing i.e. any mobo with 4 SATA ports can support it or is a special mobo required?
Unless you want hardware RAID support any modern motherboard with enough
SATA ports will do. Hardware RAID is expensive and often need propriatory
support tools. Software RAID is built into the Linux kernel and the
software overhead is rarely noticeable. Ignore the marketingspeak phoney
RAID added to some mother boards, just count the total numer of ports.
> 4) I'd need a case which allows hot swapping - or is it easier to just get 4 SATA caddies - one for each 5.25" drive bay?
See [2] and [3].
> 5) Is there a distro which makes this easy(er than others) something a la Smoothwall for firewalls? Ubuntu is my distro of choice but I have a feeling setting something low level like this up could well be very tricky. A lot of the stuff google has thrown up in this area seems to be out of date.
Don't know of a NAS distro. Basic RAID support should be in all of them
these days.
> Overall - is this a feasible DIY project of should I just save my pennies and buy it whenever I can afford it?
Definitely feasible. Like all such projects however it won't save you
money as soon as you put any sort of hourly rate on your time, it's
marginal on hardware costs in any case. On the other hand it's probably
an excellent learning/personal development project.
[1]
http://www.mini-itx.com/store/?c=50
[2]
http://www.overclockers.co.uk/showproduct.php?prodid=HD-018-BT
[3]
http://linitx.com/viewproduct.php?prodid=11999
--
Bob Dunlop
