Coda File System

Re: CODA and crash recovery

From: <>
Date: Thu, 03 Jul 2008 06:39:32 -0400
Hi Yves,

On Wed, Jul 02, 2008 at 10:58:30PM -0600, Yves Dorfsman wrote:
> Thanks Rune. I think I am going to give up on CODA for now. I am running a 

That's a pity. It looks like I have persuaded you that Coda is
far too complicated and inconvenient, which it is not.

> single server setup (one server for file sharing, mail, web, etc...) and I 
> want to keep to a low power configuration, so I do not want to distribute 
> the functions to different server, therefore my server needs to also be a 
> client.

It is perfectly possible to have a client on the server machine,
and in fact very convenient for administration. E.g. volume creation
implies both server-side (creation) and client-side (mount point creation,
acl setting) operations, handy to be able to do on the same machine.

You just have to be prepared to the client going disconnected
once in a while and as the result also having somewhat higher probability
of creating/encountering conflicts.

> Add to that the complexity of the authentication, I was really looking at 
> CODA for home directories, but the authentication scheme makes it very 
> complicated.

There is no complexity besides the one corresponding to the functionality.

The extra complexity arises in the for Coda "unnatural" situations:
clients bound to a certain realm and the host login bound to file system
Coda is definitely a bad "substitution for NFS", as well as NFS is an awful
solution for distributed file access.

Begin from scratch instead of building on your NFS experience (that's hard!)
and likely you will find it less confusing.

The role of home directory becomes different with global file availability.
Instead of the variable "$HOME" you can use a _constant_ path to where you
find your files on Coda. (As a lot of software relies on $HOME, either
reset HOME or put symlinks in the $HOME directory - and you easily
access your files which are elsewhere on Coda)

(this does not work with NFS as you never know for sure
where a certain "network share" will be mounted on some machine, if at all.
Coda does not depend on mounts)

As soon as your 6 users learn how to clog you may just skip any adjustments
on the clients. Think, no more tweaks in fstab!
Then your users will be able to use the data from anywhere also, in exactly
the same fashion.
(Not a remarkable difference compared, say, to logging into a web site)

If you really want an experience similar to NFS,
which means "certain clients only but no extra authentication steps",
then you may e.g. give the users small local home directories
with the purpose of storing their Coda passwords in a protected way locally
and running clog at login automatically.
The rest of their files may comfortably reside on Coda.
This is more complicated but it works about as good (or as bad) as NFS :)

Nothing of the above implies a need for Kerberos, Coda is happy with its own
password database.

> I might look at it again later, there are a lot of things I like about it, 
> but right now those two issues are show stoppers.

You are welcome back to the Coda club anytime :)

Received on 2008-07-03 11:07:06