On Thu, Sep 11, 2008 at 11:53 PM, Olivier Nicole <on AT cs.ait.ac DOT th> wrote:
> Is there a mechanism in Amanda to ensure that only a single tape
> changer process is running at any given time?

No -- and this poses a problem for processes that want to move data
between devices.  I'm working on such a process, and for that reason
I'm working on an overhaul of the changer API at the moment.  The key
problem with the existing API is that it has no way to indicate that a
process is finished with a device, and that the changer can load a new
volume into that device.

> Is there any mechanism in Amanda that prevents two processes that
> access tape to be running at same time (dump, flush, restore,
> recover)?

The "$logdir/log" file gets locked via amflock by any process that
accesses the tape drive.  This is much more exclusive than necessary,
but it is effective.

Dustin

-- 
Storage Software Engineer
http://www.zmanda.com