[wplug] NFS Availability Issues -- more info on your network ...

[Jonathan Billings]

Bryan J. Smith wrote:
> On Tue, 2007-09-11 at 12:41 -0400, Michael Semcheski wrote:
>> But I imagine if we do change things up, it will be to go to AFS,
>> which from what I can tell has better availability.  (through
>> local caching.)
> 
> Yes and no.  Yes, it has caching.  But no, I've never gotten the OpenAFS
> implementation to work well for anything but read-only.  But that may
> have changed in more recent months.

AFS certainly has read-write support, and has for decades, and OpenAFS 
has existed since 2000.

OpenAFS is a possible solution, however, the "local caching" won't help 
you if your only volume server goes offline, it's really only useful for 
speeding up frequent reads to the same file.

You can have multiple replicas of the same volume, in case one volume 
server goes down, but that'll only work for read-only replicas, and 
since AFS has a built-in preference to use the read-only volume, it's 
not terribly useful for /home.

Also, keep in mind that running an AFS server isn't as simple as 
exporting a filesystem, like in NFS.  You need dedicated partitions that 
  store the data, and the only way to access that data is through the 
AFS service.  You need to run several other AFS daemons which manage the 
database and volume management.  Also, you'll need a kerberos 5 server, 
and your users will need to have krb5 principals for their AFS tokens.

-- 
Jonathan Billings <billings at negate.org>