Coda File System

RE : Questions of architecture...

From: EXT / FOCAL CASSUTO Marc <ext.focal.cassuto_at_sncf.fr>
Date: Thu, 12 Aug 2004 16:56:47 +0200
Hi Ivan,

To explain my configuration is 2 squid servers
on separates physicals servers but sharing datas
(ACLs) through coda.

> a word of caution first, any given file should not be 
> modified by both clients at the same time, otherwise you get 
> a conflict (and you do not want that).
This leads to other questions :
when connected, does venus apply changes to server directly
or first work with its cache ?
In the first case the window for a risk of conflict is smaller.

How coda deal with large file ?
Suppose you modified a 10Mb file, venus is uploading the file on the server.
At the same time, the other client start modifying the same file.
Will this situation leads to an inconsistency ?
 
 
> > What is the more reliable method :
> > - using server/server replications
> > - using venus fonctionnalities (connected/disconnected mode)
> In your case I would go for just one Coda server. During its 
> downtime the clients would not be able to fetch files missing 
> in the caches, nor see each other's updates, but on the 
> positive side you never get server-server conflicts which can 
> be tricky to resolve. Local-global conflicts can be "solved" 
> in the worst case by reinitializing the client cache, losing 
> some updates, but easily.
> 
> With other words, administration of a single server setup is 
> simpler. Harder to do a "disaster recovery" if the hardware 
> breaks, but you should have working backups at hand anyway.
Hmm... But during the failure of the only coda Server, clients
continues to modify their datas. 
After the server come back, can we easily recover datas from the clients ?

Thanks,
Marc.
Received on 2004-08-12 11:03:11