Coda File System

introductory mail and questions

From: Remo Strotkamp <>
Date: Thu, 28 Oct 1999 16:46:23 -0400
Hi folks,

this is my first mail to this list!!!! So this might be quiet long, but
PLEASE read it because it contains lot's of infos, some question
and an opportunity to have a huge fileserver test candidate!

I work in a research lab, and my decided that it would be really cool if
we would
use coda as a fileserver. He gave me the job of preparing everything and
it and make the setup.

First of all let me explain the specs of the system:

It is a PIII500 Mhz  (can add a second one), with only
128MB for the moment ( 3slots free) and 8 (yes eight!!!!!)
20GB IDE Harddisk connected with Ultra66 controllers
(1 hd/bus).
The system will be running linux.

We basically had the follwing setup in mind:

Put /boot on every hd. Use Raid-1 for the rest of the linux
stuff (minimal config) on all 8 disks. And use the rest for
coda by RAID-5'ing the remaining space (~138GB - Swap).

Now I have done some background checking on coda and found out
that it does not scale that well.
Especially there seems to be this hard limit of 1GB of RVM, which
results in
25GB data space, if you count 4% as mentioned in the HOWTO.

Now this is largely below our expectations, but we are not yet giving up
idea of coda, that's why I am writing here.

I would like to know what you guys think to do best with that machine
and coda!!!!!!

I have already thought about a second setup which is based on the
size-restrictions of
coda and an e-mail in the archives which said sth about multiple servers
on one machine:

Just RAID-5 (or 1) the linux part.  Then use one server for each
remaining harddisk (6 or 7).
Each of the server would like that have 20GB of space - RVM - Log.
Like this we could use the replication capability of coda to replace our
'RAID-5 over the coda'!
This would be of no help if the machine crashes, but if a harddisk fails
it would have the same effect as
RAID-5 (even bether, depending on the volume replication used). Several
server would also give us
more freedom to play around with the capabilities of coda!

The problem now is, that I can't judge how resource hungry coda gonna
be, and how many servers I can
put on a machine with 1 (or 2) PIII 500!!!!

This immediatly leads me to another question (actually two):

In the howto on page 13 (about the fileserv config), there is mentioned
that the servermachine
needs virtual memory the size of RVM + 6MB(server) +other soft!!!!!
Does this now mean that for my linux server I need swap space equal to
that size minus the real memory
I have???  Or does this restriction apply to the address capability of
my OS and the machine????

The other question concerns an e-mail to this list from Jan
(, the 17th of october, concerning 'largest
coda server size' where he writes that:

"The real limit largely depends on the amount of real memory vs swap
space in the machine!!!"

Could anybody try to give me some more information about this Real
memory vs swap space issue.
So that I could find out how much real memory and swap I will need per
server of 20GB and as a
result how much of it on the machine!!!!!!

I think that's it for the moment.
I am sorry for the length of the mail, and hope somebody gonna read
through it!

If something is not clear from the above explications, don't hesitate to
drop me an e-mail.

thank you all very much in advance


PS  Is the above mentioned system of any interest for the coda group???
(Found this mail
       in the archive about coda and bazaar and needing testers for
large from

PSII:  Tried to subscribe to the mailing list today, but never got any
confirmation. So I don't
          know whether it is just slow, or I have done sth wrong. Anyway
please reply directly
          to me. (At least as well as to the list in case I did not
suceed to subscribe)
Received on 1999-10-28 16:47:43