On Wed, 14 May 2003, Paul Bijnens wrote:

> Jon LaBadie wrote:
>
> >Why?  Just in case it might "squeeze in"?
> >
> >
> Yes, it might squeeze in.
> I have to think a little more about the pros/cons of doing it the other way.
> Wasted time is only a minor issue for most people, I believe.


Perhaps for most people, I don't know "most".  I do know I had a
situation in my tape cycle a few years ago where the wasted time
was considerably more than what Jon described here.

I had one really large DLE that would almost fill a DLT4000 tape
when it's level 0 came up.  Consequently it took a long time to get
onto the holding disk and was always the last DLE of the run to go
out to tape.  The incrementals from all the other DLE's on that day
were always just big enough to make this DLE not fit on the first
tape.

The end result was that I had maybe 5-10% of the 1st tape taken up
with useful data, followed by a lengthy idle period while getting
this DLE's level 0 onto the holding disk (it was smbtar, so this
step took a long time), followed by something like 4 hours of
writing most but not all of this level 0 to tape 1, followed by 4+
more hours of writing this whole level 0 again on tape 2.

It was more than once that I had to tell someone who was asking
for a restore: "Sorry today is the day that backup takes all day
to finish.  I can do your restore tomorrow."

If amanda had just skipped directly to tape 2 it would have finished
around lunch time and I could have said "I can do your restore this
afternoon."

-Mitch