Coda File System

Re: Some doubts in Newer Coda

From: <>
Date: Sat, 10 May 2008 16:07:16 +0200
Hello Dhiraj,

On Sat, May 10, 2008 at 12:53:12PM +0530, wrote:
> As per your suggestions I installed the Coda Installers provided by Aetey
> softwares.

Nice to hear it worked for you.

> But then I was hit by the concept called "Realm". I want to have more
> information about Realms. What is a Realm? How do I configurations for
> Realms? How are Realm helpful?

This concept makes it transparent to access e.g. your servers
from any Coda client in the world without any specific client administration.

A realm is a collection of Coda servers which share authentication
data and are administrated together. From the client's point of view
a realm is a directory immediately under /coda.

The directory name is looked up in DNS via SRV records and as a last resort
via A record, to translate it to a set of servers' ip addresses.
The client then talks to the servers to find out the contents of the root
volume of the realm and the location of other volumes, if it encounters
mount points.

> The thing is I wish to create a large storage server for storing my
> terabytes worth of data on cheap systems with around 200GB hdd. I was
> successfully able to this using coda 5.3.20, by creating volumes for each
> storage server and then mounting  each data server on coda client as a
> separate volume. This provided me the scalability. But with the inherent
> bugs in the older version; coda is creating problems. Hence I went for the
> new coda installer. But now I don't know how realms are going to help me
> in this and how should I configure the realm so that it supports my idea
> of a scalable storage server.

You can place volumes on multiple servers and connect them together
into a tree via mount points. All data will be accessible under

> I 2 more doubts:
> 1) I was using rvmsizer.c for checking the RVM size on my server. Now the
> thing is rvmsizer shows 2 different RVM size; one based on object count
> and one on 4% rule. Which one is correct?

For simplicity you may ignore the 4% rule.

> 2) Suppose if my disk space gets full with my RVM still somewhat free. How
> will Coda respond to that.

Stores to files will fail
(which presumably will manifest itself in a conflict)

> Also if my RVM  gets full but my disk space still has some space free. How
> will it respond in this situation?

The server will most probably either loudly complain or go down or both.
Reintegration from the clients will fail and presumably lead to conflicts
as the indication.

Best regards,
Received on 2008-05-10 10:12:31