[OpenAFS] why afs backup is so poorly supported (Was: Backup AFS with BackupPC?)

Adam Megacz megacz@cs.berkeley.edu
Sun, 08 Oct 2006 15:18:23 -0700

seth vidal <skvidal@linux.duke.edu> writes:
> I'm curious about why that's so and why none of the major open source
> backup software has support for afs.


When AFS decided to go with a proprietary on-disk volume format, it
isolated its backup requirements from those of all other network
filesystems.  Because of this isolation, there is insufficient
motivation for backup software writers to expend the extra effort
needed to support these unique requirements.

Same argument applies to journalling technologies.  AFS essentially
creates a filesystem-within-a-filesystem which *still* doesn't have
even the most basic journalling capabilities -- five years after they
became a standard feature on server OSes.  Ditto for redundant
superblocks (way more than five years on that one).  And efficient
support for small files (think RieserFS as backing-store for any other
network fs).

There are plenty of good arguments for why some AFS users and
administrators benefit greatly from the special on-disk file format.
Unfortunately for some of us none of those arguments apply. =(

In the meantime, however, I will be happy with the fact that there is
at least one network filesystem out there that gives me a unified
namespace, ACLs, callbacks, and aggressive client-side caching, and a
free implementation for all major platforms.  Those five features are
*well worth* the awkward backup situation.

  - a