Thanks very much. I understand it now :)
Timothy.
-----Original Message-----
From: David Chapa [mailto:david.chapa AT adic DOT com]
Sent: 07 November 2003 18:35
To: Timothy Arnold
Cc: veritas-bu AT mailman.eng.auburn DOT edu
Subject: RE: [Veritas-bu] RE:
Yes, NBU frequency scheduler works based on a hierarchy, so if you have Daily
schedules that run every day, weekly full backups that run every 7 days and
monthly full backups that run every 28 days, the scheduler will be intelligent
enough to make the right decision as to which schedule should run, given the
window is open. So here's an example of how the scheduler works (hopefully the
formatting with the tabs makes it through-if not let me know and I'll create a
jpg or something).
Example
D1-Daily (every day)
W7-Weekly (every 7 days)
M28-Monthly (every 28 days)
S M T W Th F S S M
T W Th F S
1 2 3 4 5 6 7 8 9
10 11 12 13 14
D1 D1 D1 D1 D1 D1 D1 D1 D1
D1 D1 D1 D1 D1
X X X X X X W7 X X
X X X X W7
X X X X X X X X X
X X X X X
S M T W Th F S S M
T W Th F S
15 16 17 18 19 20 21 22 23
24 25 26 27 28
D1 D1 D1 D1 D1 D1 D1 D1 D1
D1 D1 D1 D1 D1
X X X X X X W7 X X
X X X X W7
X X X X X X X X X
X X X X M28
So if you take a look at this, what you basically have are open windows daily
for your D1 schedules, open windows Weekly for your W7 schedules and open
windows Monthly for your M28 schedules. Even though you have open windows for
D1, W7 and M28 on the 28th day of the month, NBU will basically request the
schedule that is the "oldest". So it looks at D1 and say, saw it yesterday, W7
saw it seven days ago, M28 saw it 28 days ago, M28 has to run.
So now implementing the schedules as I outlined in the original email would
look something like this. So I want all of my Weekly Full Backups
(W5) to run every 5 days, but to ALWAYS try to start on Thursday let's say, BUT
its okay to use Friday and Saturday as "make-up" days in the event of failure.
As you can see if I open a window on Thursday and the backups are successful
when Friday rolls around the logic within NBU says, okay, seen D1 two days ago,
seen W5 yesterday (do not need to see this again for 5 days), let's run D1.
However, if the backups fail on Thursday, the logic says I haven't seen D5 now
in more that 5 days, it needs to run...same for Saturday if it fails on Friday.
Now if it was finally successful on Saturday, the next time it will run is 5
days later or Thursday. And I use the same logic for my Monthly full as well.
D1-Daily (every day)
W5-Weekly (every 5 days)
M26-Monthly (every 26 days)
S M T W Th F S S M
T W Th F S
1 2 3 4 5 6 7 8 9
10 11 12 13 14
D1 D1 D1 D1 D1 D1 D1 D1 D1
D1 D1 D1 D1 D1
X X X X W5 W5 W5 X X
X X W5 W5 W5
X X X X X X X X X
X X X X X
S M T W Th F S S M
T W Th F S
15 16 17 18 19 20 21 22 23
24 25 26 27 28
D1 D1 D1 D1 D1 D1 D1 D1 D1
D1 D1 D1 D1 D1
X X X X W5 W5 W5 X X
X X W5 W5 W5
X X X X X X X X X
X X M26 M26 M26
Remember even if your W5 backup runs on say Friday, five days later would put
it at Wednesday, but since there isn't an open window for it, the backup will
not run until the next available window of opportunity, which in the example,
is Thursday.
I hope this makes sense...if not let me know...but this is a pretty powerful
feature with the Scheduler. Hopefully I was able to do it justice here.
David A. Chapa D Technical Advisor, Technical Marketing ADIC
720.249.5836 david.chapa AT adic DOT com
Pathlight VX - Integrated Disk-to-Tape Backup - http://www.adic.com
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