[OpenAFS] Info on AFS

[Hartmut Reuter]

Russ Allbery schrieb:
> 
> Charles Clancy <security@xauth.net> writes:
> 
> >> *    Migration to different media?
> 
> > Like what exactly?  Floppy?
> 
> Usually what that sort of bullet point refers to is taking infrequently
> used data and migrating it to tape, saving disk space for more frequently
> used data.  Taken to its logical extreme, you can view the disk storage as
> a cache for one's full file system, which is stored on tape.
> 
> This is sometimes needed by sites dealing with extremely large data sets,
> most of which is infrequently accessed.
> 
> OpenAFS has no native support that I know of.  I vaguely recall that some
> work was put into this at some sites, but I don't recall the details.

This is MR-AFS which is used at our and few other sites. The current
version is based on OpenAFS for all parts except the fileserver istself.
It allows datamigration into any kind of Unix-based HSM-system. We are
presently using DMF under IRIX 6.5 to do the transfer between disk and
tape, but others use SAMFS or FileServ. The main point is that files
need not to be stored in the vice-partition where the volume lives, but
can be stored also in so called shared residencies. You may have up to
31 shared residencies which can be filesystems on HSM-servers or just
disk partitions on your fileservers. You can specify size-ranges for
files in each of the shared residencies and also migration rules between
the different residencies.

Unfortunately PSC (Pittsburgh Supercomputer Center) still has not done
the step to make it open source. So to use it you need a license from
them which, however, in all cases has been granted for free. They have
abandoned the development and deployment since many years and the
development site is here.

MR-AFS also has large file support. The current CVS-version of OpenAFS
can make use of this large file support on some architectures (rs_aix42,
i386_linux24, and sun4x_58 for 64-bit machines).

Hartmut
> 
> --
> Russ Allbery (rra@stanford.edu)             <http://www.eyrie.org/~eagle/>
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Hartmut Reuter                           e-mail reuter@rzg.mpg.de
					   phone +49-89-3299-1328
RZG (Rechenzentrum Garching)               fax   +49-89-3299-1301 
Computing Center of the Max-Planck-Gesellschaft (MPG) and the
Institut fuer Plasmaphysik (IPP)
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