[Beowulf] small file systems

[Jim Lux]

At 04:58 PM 8/27/2007, Robert G. Brown wrote:
>On Mon, 27 Aug 2007, Jim Lux wrote:
>
>>And here's a challenge at the other end of the spectrum.
>>
>>What's the lowest cost, simplest, closest to off the shelf way to 
>>build a small network file server that can do DHCP/PXE booting, 
>>etc. for a compact low power cluster.  Something like a LinkSys 
>>NSLU-2 (<$100 but you need to add a USB disk, and load a new 
>>version of the OS that has dhcpd and tftpd) could probably do it, 
>>but it would be nice to have an integrated solution.
>
>An intriguing problem, but if you are serious I think you'll have to
>specify your requirements and the relative weight assigned tradeoffs a
>bit more carefully.  USB flash >>is<< remarkably cheap nowadays
>(although often slow unless you spend a bit more than the minimum) and
>there are a variety of very small devices, e.g. phones and PDAs and
>PDA-phones capable of running an OS, networking, and attaching a USB
>device or a flash chip directly.  Then there are Slugs, and then there
>are micro-ATX form factor motherboards, and then there are chopped up
>laptops.

e.g. my HTC Hermes (aka ATT 8525) cellphone has a 2GB microSD flash 
(and 802.11 wireless, and windows as well.. maybe I can get MPI to 
work?  A cluster of cellphones?)

The idea is to have a low power demo cluster that isn't cobbled up 
out of spare parts and mobos (as nifty as the various toolbox and 
bento box clusters are).

And, having a SINGLE place for the one-true-copy of the code (e.g. a 
network server) that also assigns IP addresses, etc. is a nice thing. 
(one could otherwise just put a local copy of everything at each node on flash)

One CAN buy a variety of low cost PCs that run off 12V (i.e. intended 
as CarPCs) with no hard disk, etc., usually based on one of Via's 
offerings. I have a set of 4 of them here, for instance, and they are 
a Via C3 mobo with a addon board that holds the 12V power supply and 
two CF slots.

I've looked at the "stack o'laptops" (much like the very first demo 
cluster, no?) but you're paying a lot for screens, keyboards, etc, 
and besides laptops aren't the most rugged devices in the world.




>Truthfully, I think that if one really pushed it, one could probably
>build a 50 GB solid state device (no moving parts) inside one of the
>small "paperback" portable USB disk enclosures like the one I have for
>my laptop.

There are a number of new laptops that have no hard disk, only 
flash.  Samsung has one with 32GB, Sony has one with the same (Vaio 
Type G), etc.


>   One could likely power it off of a USB cable or a small
>wall-wart, and serve the disk either over ethernet or 802.11b.  It's
>pretty easy to find functional motherboards this size or smaller for
>prices as low as $52:

ooh, but it's a mobo, and you need the rest of the hardware (PS, case, etc.)

Think in terms of running off a 12V (unregulated) supply..

But you're right, it's quite doable as a hacking project, for under a 
kilobuck (to build a server+4nodes)




James Lux, P.E.
Spacecraft Radio Frequency Subsystems Group
Flight Communications Systems Section
Jet Propulsion Laboratory, Mail Stop 161-213
4800 Oak Grove Drive
Pasadena CA 91109
tel: (818)354-2075
fax: (818)393-6875