People are still splitting mirrors? From what I can see AIX 5.2 (Oct 2002!) 
added JFS and snapshots. Removes the risk of a mirror getting merged back the 
wrong way if the break-backup-merge crashes and has to be undone by hand. 
Breaking the mirror means either you need to have multiple mirror copies or be 
at risk for a disk while split.  We back up 3x a day for the production 
database alone. Add all the other filesystems and we'd have some mirror split 
more often than not. That's not an acceptable risk to me. Not when there are 
alternatives, and better ones at that.
Plus it's a journalled file system... ever had the power yanked in the middle 
of the day? Or a panic? The fsck's alone can take hours on a large system. With 
JFS they take minutes. Still have to do the UV side, but my experience has been 
that the files will be MUCH cleaner. Pre-JFS a "unplanned" downtime took 
roughly 24 hours - post was  less than 3. 
Robert F. Porter, MCSE, CCNA, ZCE, OCP-Java
Lead Sr. Programmer / Analyst
Laboratory Information Services
Ochsner Health System
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>>> Wols Lists <> 8/19/2011 6:19 PM >>>
On 18/08/11 05:07, Chris Lee wrote:
As others have mentioned, you can pause the database. If you've got a
mirror then DBPAUSE the database, break the mirror, and DBRESUME.

You can now back up the broken mirror, safe in the knowledge that all
the files are internally self-consistent. I think DBPAUSE guarantees the
integrity of transactions, but if you backup both the /uv and the
/uvaccounts directories, then you should get the transaction logs as
well, I hope :-)

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