=> On Mon, 12 Mar 2001 15:05:10 +0100, Schaub Joachim Paul ABX-PROD-ZH 
<joachim.schaub AT ABRAXAS DOT CH> said:

> Im wondering if and how you bill up your costs on your customers.
> There was some discussion about following points:

> - pay per space used on medias
> - pay the network load also etc.


We're doing both: a small charge for transferred data and a charge per MB
stored on the server.  We don't bother differentiating DASD from tape from
optical, the whole point is that they shouldn't have to worry about that.


<speil>

When generating chargeback systems, there are basically four concerns, two of
them closeley related.

  - Cost recovery
  - Insurance against unexpected behavior
  - Behavior control
  - Marketability


Cost recovery:

     No matter what else is going on, you would like to be charging enough
that, if you got revenue for everything you did, the system would 'pay for
itself'.  I presume here that you are charging back in some sort of internal
environment, rather than selling backup to the public.

     For our site in particular, we also wanted to make sure that we didn't
undercut our other services:  It should be cheaper to rent disk from us than
to download something for the day, work on it, run an incremental, and then
delete it. :)


Insurance against unexpected behavior:

     It's important to have predictable bases covered: If someone starts doing
incrementals back-to-back, keeping only two copies, you want the charging
algorithm and SLA you initially established to cover that, and the new income
should be enough to upgrade your infrastructure.

Behavior control:

     You don't want to have to say to J. Inconvenient Customer, "Don't take up
so much space".  You want to _bill_ her, and buy more tape robots.  Then all
of the customers are in control of their usage and fees.  If (as do I) you
have a customer who prefers to keep 40 copies (actually more!) of their
backups, then that's in their power, they just need to arrange their
configuration so their risk / pain ratio is in their comfort range.

Marketability:

     Once all these things are taken care of, you'd like to have charges as
low as is possible, because you at least theoretically want customers. :)

     It can be hard to communicate just _how_ good *SM service is, if your
audience is folks who are accustomed to tossing in a tape every week wether it
needs it or not.


</speil>


Allen S. Rout
UF *SM type