What Ed said.
... and I'll add two and a half comments ...
(1) A retention of twice the frequency is way too short a retention for
my taste. A retention of one week is too short for anything! Remember
that it's one thing to discover the need for a restore in a certain time
period, but quite another to discover the problem *and* get the restore
completed. For example, perhaps a minor server goes down and won't be
repaired/replaced for a week. You've got excellent ability to restore
your last backup today, but will you in a week?
(2) Make sure your scheme is grounded in what the data owners require
for restorability. This describes a "complicated" (IMHO) backup
scenario without discussing the restore commitment/expectation. Without
knowing what's behind it, it looks like a design that uses NetBackup
features rather than solves a particular problem. For example, in your
shop is there much of a difference between cumulative and differential
incrementals? To my mind, the only reason not to do a full is that you
can't "afford" it, in some sense. Likewise, never do a differential if
you can afford a cumulative. It shortens restore times and lessens risk.
(2 and 1/2) Advice to limit data to only one retention period on any one
tape is normally good advice, IMHO. You have 4 different retentions,
suggesting this scheme may require more tape drives than a simpler one.
Of course, backup to disk and multiplexing affect this area.
(2 and 3/4) Bonus advice. A full backup every three months is way too
long, IMHO. It might be OK for some very static systems, but I've not
seen them. Make a substantial change and you'll be backing it up a lot.
Better to make more frequent "Fulls".
(2 and 5/6) Is there a need for separate offsite storage? How does that
affect the plan?
Hope this helps, or at least gets a discussion going!
wayne
Larsen, Errin M HMMA/Information Technology Department wrote, in part,
on 7/18/2005 2:54 PM:
>Hi NBUers,
>
>I'm trying to create a set of schedules for a policy as follows:
>
>1) Full Backup, retention 1 year, every 3 months (1 time per quarter),
>on the 1st Sunday of that month
>
>2) Cum. Incr. every month, retention 2 months, on the 1st Sunday of that
>month (excluding the month of the full)
>
>3) Cum. Incr. every Sunday, retention 2 weeks (excluding the 1st Sunday
>of that month)
>
>4) Diff. Incr. every Mon - Sat, retention 1 week
>
>Please, comment/critique on the design.
>
>I'm writing to the list, however, to get advice/help on implementing
>this. What kind (Calendar/Frequency) of schedule works best for this
>kind of thing?
>
>--Errin
>
>
>_______________________________________________
>Veritas-bu maillist - Veritas-bu AT mailman.eng.auburn DOT edu
>http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu
>
>
|
