Noel Lindsay Hunt writes:
> > I would never exclude these paths from regular backup.
> 
> But isn't it likely that while NetBackup is writing into
> the db directory file sizes will change and hence a
> (normal) backup of those directories could be
> inconsistent?


Yes, it is.  It's quite likely that only about 99% of the backup would
be useful.  And it doesn't really protect you against a complete
catalog loss (unless of course you know what tapes the backup went
to).  This is why you need to backup the catalog using the
normal procedure.

But, that catalog is almost totally a collection of more or less
unrelated pairs of files.  In the event of damage to the catalog,
which is not caught before two catalog backups have occurred, having
99% of my catalog available from a regular backup at least gives me a
chance to recover without having to scan every tape I may have ever
used.


For example, let's say I'm writing a script to expire a bunch of
backups from my mysql-devel machine.  On Thursday, I'm testing the
script and it seems to work great.  Full backups run over the weekend,
and the NetBackup catalog gets backed up a few times.

The following week, I get a request to do a restore for some files
from my mysql-prod box.  Funny, I can't find any backups before this
weekend.  Uh-oh.  I check my script, and sure enough, I've
accidentally deleted my production backups.  I can't restore from the
NBU catalog backup tapes, because they only have copies from the last
couple days.

How does the story end?  Pick one:

1) Fortunately, I've been backing up my NBU database as a regular
backup as well.  I restore the pertainent database files from the
image directories.  Checking the headers, I figure out which tapes the
data resides on, make sure they haven't been reused, make sure they're
assigned, and do my production database restore.  Or I could just
restore the header files, figure out which tapes I need, and import
them.

2) I've excluded my database files from regular backup.  The first
   thing I need to do is ensure that no tape in my environment that
   isn't brand new gets used until I straighten things out.  As if
   that isn't bad enough (and it's pretty bad if you think through the
   logistics), I get to import every single tape that might have
   contained those backups.  All of this while my phone rings every
   five minutes asking for an ETA.


The same argument can be made for taking a database tape out regularly
and putting it somewhere (like using Vault, and always sending a copy
of the NBU db with the offsite tapes).

HTH,
L
-- 
Larry Kingery 
       Computers are not intelligent. They only think they are.