"Physical backups are the foundation of any sound backup and recovery
strategy. Logical backups are a useful supplement to physical backups
in many circumstances but are not sufficient protection against data
loss without physical backups."

Now, what they might mean here is not losing any transactional data,
and for your organization it may seem sufficient if they "only" lose
half a days work.  (From what I've seen, such a judgment usually comes
from faulty risk analysis.)

But...

What is also implicit is that you need redundancy in any recovery
plan.  You need to remember, any given backup, logical or physical,
may be unusable for a variety of reasons.  With a logical backup, if
one is bad, you can only go to the previous.  If that one is bad, the
one before that.  And so on until you realize you are TSOL.  With
physical backups, it is possible to have multiple copies of archived
logs in various backups (as well as online), so it may be possible to
go to an earlier backup and apply logs as much as desired.  In
addition, as others have alluded to, RMAN has additional capabilities
for corruption detection and repair.  Beyond that, there are newer
features based on archive logging that allow recovery without even
bothering with the backups.  There is also the occasional glitch doing
an import.

The logical backups are really for moving data around (that would
explain the data pump name, right?), and in some cases recover some
data from a previous time.  They are not designed to be depended on as
a database backup.  We can't be any clearer than that:  read the
manuals.

That said, I use exp/imp all the time for various things, it is very
useful to have recent exports as a matter of course.  It's just not
for primary backup purposes.  You might also be taking note of any
effects on your undo if you are exporting during transactional time.

jg
--
@home.com is bogus.
"When a meteorologist says 'we'll be back with tomorrow's forecast,
right after this,' he's trying to sneak away to the bathroom. Some of
the more relaxed ones are actually catheterized, with a tube running
down their pant leg and into a bottle strapped just above the ankle.
The camera never shows a meteorologist below the knee, and now you
know why." - Dr. Science

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