RE: Can Log Files Be Archived To The Bit Bucket?

  • From: "Pal, Raj" <Raj.Pal@xxxxxxxxxxxx>
  • To: <jim.silverman@xxxxxxxxxxx>, <oracle-l@xxxxxxxxxxxxx>
  • Date: Thu, 5 Apr 2007 14:31:43 -0600

Jim,

Yes, you're missing a key component.  No worries... that's why we're all
here to help eachother.

To start, I think you misunderstood my proposed solution (which, by the
way, may not be the best one... just the first I thought of).  Assume
that your arc format ends in ".arc".  So all your sequenced logs are
/arcdest1/<blah>_1.arc, /arcdest1/<blah>_2.arc, etc...  Now you back
them up, maybe 4 filesperset (hypothetical) so that seq#1-4 are found in
/arcdest1/<backupset_some#>.delete.

You are correct that the ".arc" files will be deleted since you used the
'delete input' clause.  But nothing other than an OS command will remove
your <backupset_some#>.delete files.

With the level0 and level1, assuming an open instance, your blocks WILL
be blocked up without fracture.  But they will NOT be consistent.
Without archivedlogs, you CAN restore your database... but you can NOT
recover it... so it's essentially useless since it can't effectively be
opened.

For an instance to be "openable", archived logs MUST be available from
the SCN (or time) of the first block being backed up, through to the SCN
(or time) just after the last block was backed up.  This is why the RMAN
utility will error out if you attempt to backup an open database in
noarchivelog mode... it knows that it can't recover it.

Keep asking until it makes sense!

--------------------------------------------------- 
RAJ@xxxxxxxxxxxx


-----Original Message-----
From: jim.silverman@xxxxxxxxxxx [mailto:jim.silverman@xxxxxxxxxxx] 
Sent: Thursday, April 05, 2007 2:19 PM
To: Pal, Raj
Subject: RE: Can Log Files Be Archived To The Bit Bucket?

Raj, thanks much for the response.

First, you're right:  we would never take this approach in a production
database.  In fact, our production instances are already being backed up
with rman, including the archivelogs (of course).

Second, what you're proposing is similar to what we do with our
production backups, except that we don't need to explicitly include the
"rm ..." in the script, since the rman "backup ... delete input" takes
care of this.  What we (well, actually, my manager) is trying to avoid
is allocating the disk space for the archivelogs.  I'm pretty convinced
at this point that we're going to have to do so, but I figured I'd ask
the gang for any creative ideas that won't require more effort to
implement than just doing it right in the first place.

Finally, as an aside, I'm not sure why the logs would be needed during
the L0s and L1s.  I just thought that rman would back up the changed
blocks from the datafiles, which could then be reassembled during a
restore/recovery operation.  It wouldn't surprise me to learn that I'm
missing a key component of the formula, but I don't see it yet...
=====================================
Jim Silverman

-----Original Message-----
From: Pal, Raj [mailto:Raj.Pal@xxxxxxxxxxxx] 
To: Silverman, James (TH USA); oracle-l@xxxxxxxxxxxxx
Subject: RE: Can Log Files Be Archived To The Bit Bucket?

>On Behalf Of jim.silverman@xxxxxxxxxxx
>Sent: Thursday, April 05, 2007 1:11 PM
>To: oracle-l@xxxxxxxxxxxxx
>Subject: Can Log Files Be Archived To The Bit Bucket?

>We manage several non-production 10g databases that are currently shut
>...
>Thanks in advance for any suggestions.
>=====================================
>Jim Silverman

Jim,
You'll need archives for the duration of the level0 and level1 backups
...
Once complete, startup your backup/delete script again.
...
--------------------------------------------------- 
RAJ@xxxxxxxxxxxx
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