[OpenAFS] a few open afs questions...

[Nathan Neulinger]

>   Also, what if two people modify the same document at once?  Ideally, I
> would like to put things like "/var/spool/mail", web pages and perhaps
> databases on it.  Oh yeah, does play nice with RAID 5?

I don't know about the block level changes to files that would occur
with databases, I'd be inclined to avoid that.

Mail - go with a maildir format spool and you should have no problems at
all. You can use a standard mbox style spool, but you're much safer with
a maildir spool as it doesn't need to do any locking, and it is safe to
be accessed from multiple clients simultaneously.

As for web pages, I'd say that based on how most editors save files
(write out the whole new file as opposed to changed pieces), it will be
the last person to close the file. Now, if they are on the same afs
client box, that behavior will likely be different, since they'll be
accessing the same instance of the file in the cache, but I don't know
enough about the low level behavior to know for sure.

As for raid 5, that's purely a filesystem issue. AFS shouldn't care. We
use hardware raid 5 on all of our transarc-afs file servers. 

-- Nathan

------------------------------------------------------------
Nathan Neulinger                       EMail:  nneul@umr.edu
University of Missouri - Rolla         Phone: (573) 341-4841
CIS - Systems Programming                Fax: (573) 341-4216