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Re: [Bacula-devel] vtape

On Wednesday 25 June 2008 20:34:05 Eric Bollengier wrote:
> Hi,
> On Wednesday 25 June 2008 14:36:50 Kern Sibbald wrote:
> > Hello Eric,
> >
> > For those of you who don't know what vtape is -- it is a virtual tape
> > driver that Eric wrote that simulates a real tape drive but using disk --
> > it is no small programming accomplishment!
> Thanks :)
> > Nice work!  I just "converted" my test regression case so that it is
> > vtape/tape neutral.  It works like a charm.  One can switch back and
> > forth between vtape and real tape by simply changing:
> >
> > USE_VTAPE=yes
> > to
> > USE_VTAPE=no
> >
> > or vise-versa and then running:
> >
> > make sed
> >
> > I ran my test tests/two-vol-manual-tape both with a real tape drive and
> > using vtape with the above procedure and diffed the output.  The only
> > differences were due to dates and timing (i.e. vtape runs much faster) --
> > everything else in the debug output listing was identical.
> >
> > I'm looking forward to finishing up version 2.4.1 using vtape (*much*
> > faster)
> vtape isn't present on 2.4 branch...

Yes, that is correct, but that was a bit too complicated to explain, and much 
more important, 99,9% of the code in the trunk that does have vtape is 
identical to the 2.4 branch, and where it differs, it is very easy to 
backport (except for reserve.c, which is a pain.

> > so you can move all the @xxx@ variables to the environment, and
> > then there will be no need to even run the "make sed" script to switch
> > between real tape and virtual tape.
> We will have some problems with bacula configuration file, how do you want
> to handle that ?

I think that the configuration parameters can also be environment variables.  
If you change variables that affect the configuration, you will need to 
rebuild, but as far as I can tell in the experiments that I have done, no 
reconfiguration (i.e. no ./configure --options) is needed to switch from real 
tape to vtape.

> We can do some sort of "make sed" during regress test initialization for
> example.

Yes, that is essentially what I currently do manually.  It is quite easy.  

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