Coda File System

RE: Come-and-go system with data replication

From: <josef.schwarz_at_bt.com>
Date: Tue, 28 Oct 2003 08:49:31 -0000
> No you have to let the two servers started, running, in order them to 
> replicate all data....
> When one is down for a while, everything work corectly 
> because there is 
> still one up that could hang the work...
> And when the down server get back up, he will syncronize and  get all 
> new data automaticaly...

No, but the point is that I want it to be more flexible. The system shall not be dependant that the absent server comes back, another server should take over his position. 
So that's not possible with Coda, is it?

> >I think a server needs to be restarted when another one is 
> added, so it's probably better to have only two or three 
> servers in the network (probably with Coda it's not possible 
> for all nodes to work at a client and server at the same time). 
> >
> Don't understand.... sorry...

I am just thinking in terms of Peer-to-peer, with a node being client and server at the same time (which is good for Come-and-go behaviour). With Coda, this is hardly possible, however, due to the fact that a server needs to be restarted when another one is added - that's right, isn't it?

> - STOP thinking in IP... you are going in such a complicated 
> way for a 
> couple of day , getting aroud modifying conf files / commands !! I 
> really think you are in a wrong way of work...  Try to make it work 
> correctly,  before modifying things and go into  no-ways !
> ( there is enough to do !!! )

Well, IP addresses rather than hostnames... It really seems that the set-up with IP addresses was no good idea. And that's one thing I don't understand - how one can design a system which can not handle IP addresses at the same time; it should not be that much effort, one check if it's an ip address and when it is one, skip the gethostbyname()?

> 'cfs lv /coda/172.16.1.1' and 'cfs lv /coda/172.16.3.1'
> 
> That mean you have two clusters !!!!!

Sorry, I don't know what you mean. I am not working with clusters. The reason that the two clients seem to be in different subnets is that the underlying vpn infrastructure requires it.
But this really should not matter, since the appropriate files are adapted, and it is working basically.

> And you are trying to set up  :
> - 1 cluster of two server
> - a /coda/my_first_cluster-realm_name/public/  directory...
> with /public that would be a volume replicated on 172.16.1.1 and 
> 172.16.3.1 no ???

Well, I thought that it should be working like that, that the data needs to be the replicated on 2 servers so that it is redundant. So what's your point? Am I missing the point?

> Did you succeed in creating a replicated volumes ???

I described the outcome in the email "Replicate the root filesystem".

> Perhaps the better advice  : I think you'd better start again from 
> scratch.....
> Your are such in a complicated way that you had mis-understand the 
> concept, and certainly some commands....
> Moreover i think there will probably be part of the coda-code 
> that don't 
> work because you have a "fancy" configuration !

:) What's so fancy if I want to use IP addresses instead of hostnames?

> Hang on.... read a lot...  Google(tm) and the mailing list archive is 
> your best friend...

Thanks for advice, I think I have never read that much in mailing list archives and got so little actual help out of it than with the one of Coda.
And it really makes me thinking about giving up, when I find messages like this one, where a similar but easier configuration did still not work after a whole year...
http://www.coda.cs.cmu.edu/maillists/codalist/codalist-2001/4000.html

> Everybody  get difficulties at the begining... but you can 
> overcome !!!!

A problem with Coda is not the lack of documentation but the fact that it is not consistent, that files are in different locations now, behaviour has changed, and probably just the absence of some example configurations. I know that Coda is nothing for beginners, I would not consider me as a beginner, however - I just think Coda is pretty confusing. That's the reason - in my opinion - that only a couple of people are using it - after 15 years development!!!
Received on 2003-10-28 04:03:32