[OpenAFS] Re: afs vs nfs

Robert Banz banz@umbc.edu
Wed, 23 Nov 2005 09:45:44 -0500

Dan Pritts wrote:
> On Tue, Nov 22, 2005 at 08:38:31AM -0500, Joe Buehler wrote:
>> - AFS storage is organized into volumes, attached to one or more mount
>> points under the /afs tree.   These volumes can be moved from server
>> to server while they are in use.  This is great when you have to
>> take down a machine, or you run out of space on it.  The users never
>> notice.
> This can also be considered a disadvantage.  When using AFS, you are
> forced to manage your storage the AFS way.  Files are effectively not
> stored natively on the filesystem, and cannot be accessed via some other
> method, and must be backed up via afs-specific methods.
> It works pretty well, but as an NFSv4 presenter put it, NFS is a network
> filesystem - with AFS you have to swallow the whale of all the other AFS
> stuff.

Which is kind of a good thing.

I mean, in AFS-land, the semantics for file access of a file available 
in AFS are the same for all users of that file.  With NFS, you have the 
choice of accessing the file locally on the fileserver, or over the 
network via NFS.  And, I'd argue that's bad.

Really, they are two different beasts.  AFS is an entire distributed 
system for file storage, authentication, and access control.  NFS(even 
v4) is simply a way of serving files that are on a particular host.