Ooo. Where can I buy this book when it comes out?
-Nate
-----Original Message-----
From: David A. Chapa [mailto:david AT datastaff DOT com]
Sent: Thursday, June 05, 2003 9:34 AM
To: Yosifovski, Tammy
Cc: 'Joost Mulders'; Veritas-bu AT mailman.eng.auburn DOT edu
Subject: RE: [Veritas-bu] Tape Predictions for Transaction Logs
It not silly.
There is a chapter in Implementing Backup and Recovery that Dave Little and
I
just finished writing that illustrates how to plan your tape capacity. It
should be easy enough to translate those formulae into trans log only
equations.
Unfortunately I am not at liberty to send you those pages right now as the
book
should be coming out this month...but the equations work...but as you
mentioned
there are a lot of variables to consider...so in the interest of simplicity
we
didn't introduce combined D-INC and C-INC backup equations but based on
D-INC
only or C-INC only...if you get the book you'll understand what I'm talking
about. Anyway, I can't take credit for the equations, I enlisted the help
from
my brother who's got an under grad in Mathematics, Masters in EE and a PhD
in
Imaging Science. So I trust his work.
David
-------------------------------------<
David A. Chapa
DataStaff, inc.
312 683 1144
mailto:consult AT datastaff DOT com
http://www.datastaff.com
Co-Author:
Implementing Backup and Recovery:
The Readiness Guide for the Enterprise
published by John Wiley and Sons
A Veritas Solution Series Publication
ISBN:0471227145
-------------------------------------<
Quoting "Yosifovski, Tammy" <Tammy.Yosifovski AT usfc DOT com>:
> Okay, Okay so my question is silly but doesn't anyone have to predict tape
> usage to charge against a capital expenditure, before actually using the
> tapes not after? I can easily do this for disk space but transaction logs
> are a whole ballpark of its own.
>
>
>
> -----Original Message-----
> From: Joost Mulders [mailto:mail AT j-mulders.demon DOT nl]
> Sent: Wednesday, June 04, 2003 5:25 PM
> To: Veritas-bu AT mailman.eng.auburn DOT edu; Yosifovski, Tammy
> Subject: Re: [Veritas-bu] Tape Predictions for Transaction Logs
>
> >Does anyone have a mathematical formula for predicting tape usage for
> >transaction logs? Any idea on how to do this for something like this
that
> >has so many variables?
>
> Hmm, let's see.
>
> ((X / (1024 ^3)) x Y) / Z) x W
>
> Whereas:
> X = The number of bytes your db's generate for transactionlogs
>
> A nice estimation of X would be, the number of users connected
> to your db x the number of keystrokes they do per day x their
> intelligence factor divided by the coffee cocient, which is an index
> for the quality of the coffee your company serves.
> 0.1 is bad coffee. 1 is very good coffee. So 0 >= X <= 1
>
> Y = is your retention, expressed in days.
>
> Z = is the capacity of one tape, expressed in GB's.
>
> W = a factor expressing the quality of the backup admin.
> W = 100 = Bad admin
> W = 1 = Good admin
> So, 1 >= W <= 100
>
> Sorry, couldn't help it. Nothing better to do :-)
>
>
> --
> You're to have, not to hold.
> _______________________________________________
> Veritas-bu maillist - Veritas-bu AT mailman.eng.auburn DOT edu
> http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu
>
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