[OpenAFS] Re: Getting started with OpenAFS

[Andrew Deason]

On Fri, 30 Apr 2010 17:49:16 +0400
Mike Pliskin <mike@area9.dk> wrote:

> Ok thanks a ton for explaining, the only point left is read-write and
> read-only and how to separate those. So far it sounds like I will need
> to have a setup like
> /afs/public/data1
> /afs/public/data2
> /afs/public/data3
> /afs/user1/data1
> /afs/user2/data2 etc

The general notion of ROs vs RWs sounds correct, but the path structure
is annoying me :) Traditionally, the convention of paths goes something
like this:

/afs/<cellname>/<volume>

for the RO path, and

/afs/<cellname>/.<volume>

for the RW path. (And /afs/.<cellname>/ provides an RW path for
anything).

So for example, you'd have /afs/area9.dk/.data1/, that some users can
write to and fiddle around with. When someone/something decides it is
time to release that data to all sites and make it 'public' via the RO
paths, the data in /afs/area9.dk/.data1/ becomes synced with
/afs/area9.dk/data1/. You 'decide' this by running a command
(specifically 'vos release'). Then people can read the new stuff in
/afs/area9.dk/data1/ by accessing one of many servers.

I'm not really sure I'm clear on your usage, though... you have data
which will be 'accessed' by geographically diverse clients. But it helps
to clarify 'access' into 'read' and 'write'. Do you have people from
multiple different sites that will be writing to the same set of data?
As far as I know, that will always be slow, since you must at least
contact the remote sites immediately, or you risk cache coherence
problems.

-- 
Andrew Deason
adeason@sinenomine.net