On Wed, 19 Feb 2003 at 2:08pm, Alex Page wrote

> I'm setting up an amanda system, and I'm a little confused by the
> jargon. What I'm trying to do is one full backup a week (on Fridays) and
> partial backups every other weeknight. I want to operate four weeks of
> tapes in rotation, so at any time we have four weeks of backup down to
> the granularity of one day.

Using amanda requires a bit of a paradigm shift in how you think about 
backups.  Amanda handles the bulk of the scheduling, not you.  The "full 
on Fridays, incrementals otherwise" is the old way of thinking of things.

> Am I right in thinking that this is a dump cycle of 7 days, with 5
> runs per cycle and 4 tapes per run? Sorry if this is alarmingly obvious,
> I'm pretty new to all this :)

Almost.  dumpcycle is the maximum time between level 0s of any particular 
disk list entry (DLE).  For you, that's 1 week.  Runspercycle is the 
number of times you'll run amdump per dumptycle -- for you, 5.  runtapes 
is how many tapes amanda can use per amdump.  Unless you have a changer, 
that's probably 1.  And tapecycle is how many tapes you're going to give 
amanda to use.  For your 4 week history, you'll need 20 (unless your 
runtapes is > 1).

Now, amanda's goal is to have each night's backups be about the same size 
(and thus take about the same amount of time).  To do this, it will spread 
level 0s throughout the dumpcycle.  It will promote dumps (i.e. do a level 
0 before one is due) if it needs to in order to equalize things.

You *can* force amanda into your paradigm, but it isn't pretty.

-- 
Joshua Baker-LePain
Department of Biomedical Engineering
Duke University