Re: Problems with hot backup via BCV's...

Jim,

Don't know if this applies in your case, but a couple of years ago I had similar problems with hot backups on AIX. It seems that if the initialization parameter log_archive_buffers was set to anything higher than 1, I had the possibility of getting "Fuzzy" SCNs (they didn't call it that, they called it corrupted SCNs). There was supposed to be a patch (has to do with the AIX implementation of AIO), but I never saw it, never changed this parameter back, and haven't had any problems since.

Regards,

David A. Barbour
Oracle DBA, OCP (still seeking the one true path) Jim Hawkins wrote:
>
> List,
>
> Oracle 8.0.4.3.0
> AIX 4.3.3
> EMC Symmetrix
> SAPR/3 4.0B
> 200,000+ transactions/day; 300GB database.
>
> Here's what we do:
> 1. Put all tablespaces in hot backup mode.
> 2. Split/Sync mirror.
> 3. Take tablespaces out of hot backup mode (usually after only 3-5
> minutes).
> 4. Take BCV backup of this mirror.
>
> Problem is, when restored, sometimes the database can be opened resetlogs,
> and sometimes it can't. When it opens, we just apply all archive logs
> generated during steps 1 through 3, then open resetlogs and it works fine.
> The other half of the time, Oracle complains that the system datafile still
> needs more recovery. You can keep applying logs and it will never open.
> Oracle had me take header dumps to check for "fuzzy SCN's", which these do
> appear to have. Oracle says this is a bad backup set even though EMC
> thinks it was fine. By the way, "fuzzy SCN's" are SCN's that have a hex
> value that evaluates to a nonnumeric, nonsensical number.
>
> Was wondering if anyone else was having issues with hot BCV backups and
> restoring them. We are current in terms of EMC TimeFinder and other
> software. It just seems to be hit or miss with these backups (obviously we
> take other backups too, but these are the easiest and most timely).
>
> Thanks,
> Jim
>
> Jim Hawkins
> Lead SAPR/3 Oracle Database Administrator
> MEMC Electronic Materials, Inc.
> 600 Pearl Drive
> St. Louis, MO 633376
> 9636) 474-7832
> jhawkins_at_memc.com (work)
> jhawkins_at_primary.net (home)
>
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.com
> --
> Author: Jim Hawkins
> INET: JHawkins_at_memc.com
>
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-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- 
Author: David A. Barbour
  INET: dbarbour_at_nucentrix.net

Fat City Network Services    -- (858) 538-5051  FAX: (858) 538-5051
San Diego, California        -- Public Internet access / Mailing Lists
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