[OpenAFS] Question about directory names

Thomas Kula kula@tproa.net
Tue, 29 Nov 2011 14:53:22 -0500

On Tue, Nov 29, 2011 at 01:44:13PM -0500, Hunter McMillen wrote:
>    Hi everyone,
>    This  is  probably  a real beginner question but why do some cellnames
>    begin  with a period? I couldn't find anything about this in the docs,
>    or  perhaps  I  missed  it  but I was hoping someone could clear up my
>    confusion.
>    example:
>    There are two entries the cell name, one with a '.' in front of it and
>    one without.
>    ls /afs/<Cell-Name>
>    ls /afs/.<Cell-Name>
>    The  cell  without the '.' has folders named: service and users inside
>    it,
>    The  cell  with  the  '.'  has folders named: service, users, bin, and
>    share.

I'm betting you will find that /afs/<cell-name> is the RO version of 
<cell-name's> root.cell volume, and /afs/.<cell-name> is the explicit
RW version of that same volume --- this is a pretty strong convention
amongst several cells that I've seen.

You can verify this with the 'fs lsm' command:

 - fs lsm /afs/<cell-name> 

   is probably going to return something like

   '/afs/<cell-name>' is a mount point for volume '#root.cell'

 - fs lsm /afs/.<cell-name>

   is probably going to return something like

   '/afs/.<cell-name>' is a mount point for volume '%root.cell'

The "#" in '#root.cell' means 'normal mount, prefer the RO version of
a volume if one exists', "%" means 'explicitly use the RW version of 
the volume".

The reason you see different contents is because someone has made new
changes to the RW version of the root.cell volume but hasn't released
it yet.

Caveat: if you're on a client doing dynroot I'm not sure what the
fs command above will actually return, since the cache manager gins up
all those entries itself, and I can never remember how it handles them.
But the reasoning behind them is the same.

Thomas L. Kula | kula@tproa.net | http://kula.tproa.net/