Re: LANs, DHCP, and local name server question

In article <sd4mj4-hng.ln1@xxxxxxxxxxxxxxxxxx>,
Martin Gregorie <martin@xxxxxxxxxxxxxxxxxxx> wrote:

When it gets old and flaky my plan is to replace it with a low powered,
preferably fanless, iPX based box (or whatever is the equivalent at the
time) that uses as little power as possible while handling the jobs I
need it to do.

Gordon, I think it was you who originally suggested iPX systems were the
way to go. I like the idea of doing this but there are a few related
questions I've thought of and can't answer myself:

- if I use a 2.5" laptop disk in an iPX system with one of the standard
distros, say Fedora, could the system be configured to let the HDD
spie down when the system is idle?

Probably. I'm not a Fedora/RH expert (Debian here), but look for the
noflushd utility. It may not work with ext3 or another journalling FS,
but I think there's something newer than noflushd - it's been a while
since I looked though - it's usually not enough to just send the command
to spin the device down - you need to make sure log-files don't get
flushed out, etc. which will cause it to spin up almost immediately.

- is spin down worthwhile with regular timed tasks (e.g. fetchmail
waking up every 10 mins to check for mail and leafnode looking for
news every hour) of would the regular spin up/down merely wear out
disks faster than using standard 3.5" drives that are left spinning?

I've no idea here - personally I'd use something like a 1-2 hour idle
period, and stop things like fetchmail running overnight.

The wear and tear factor is something that causes much sucking of
teeth... The controller board on the drive should still be "hot", so
from that point of view it ought to be OK - there's only the turn-on
from cold "shock" to it. Motors ought to spin up and down OK - they do
in washing machines ;-) OK, so slightly different technology, but...

Win Laptops will/can spin drives down as often as possible when on
battery, so it's probably OK, but they're not usually designed for
continuous running though...

- would the power savings from spinning down the disks give a
significant saving given the slug of power needed on restart?

Yes.

Well, I think so - say it's 10x the running power to spin up and it
takes 5 seconds - thats the same power as running it for 50 seconds at
normal rates.

I've built and deployed many microITX boards in recently months - as
routers and asterisk PBXs, but I boot all mine off a flash IDE device -
it loads an initrd.gz into RAM and then runs everything from RAM disk.

Heres an example:

# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/ram0 124M 55M 70M 45% /
tmpfs 245M 0 245M 0% /dev/shm

That's a router. Pretty dull. I added a 2-port Ethernet card to the on-
board 2-ports. 1GHz processor, routes/firewalls/QoS at 100Mb without
any issues.

# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/ram0 124M 68M 57M 55% /
tmpfs 125M 0 125M 0% /dev/shm
/dev/hdc2 60M 29M 31M 48% /data

that's an asterisk box - it has a 2nd 64MB flash IDE mounted as a live
(ext2) filesystem for voicemail storage... (Whether this is good or not
is open to debate!)

This is the place I get the boards from:

http://www.icp-epia.co.uk/

The CN-1000's are what I use for the asterisk boxes, the EK-1000's with
2 Ethernet ports are routers. (They have a fan, but it's termperature
controlled and I've never seen it run!) The EK-1000's will fit in a 1U
box, the CN-1000's won't because the heatsink is too large - none of
the photos show the heatsinks fitted!!!

The Flash IDE device I use is only 64MB. It's formatted ext2 and contains
nothing more than a kernel + initrd.gz and enough support to make it
bootable (/etc/lilo.conf and /dev) As it's all compressed, it doesn't
take up much space.

I have a prototype low-power NAS box with a pair of drives, which uses
this technology too - ie. boot off flash, data on the drives, but I've not
had much time recently to develop it, and the Drobo (www.drobo.com which
is nothing to do with me & drogon!) looks like a bit of an intersting
project anyway... It's not NAS, but still intersting...

Gordon
.

Relevant Pages

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