Re: Manual Standby as alternative to dataguard
- From: Ravi Madabhushanam <ravi.madabhushanam@xxxxxxxxx>
- To: sanjeevorcle@xxxxxxxxx
- Date: Wed, 17 Jun 2009 21:39:03 +0530
Sanjeev,
We are running exactly similar kind of DR site for one of our
production. I prefer to not call it a DR, but management is ok with
it. In our environment there are many temporary (in the way they are
used) tables which are loaded & deleted in NOLOGGING operation. These
operations are very critical to the application and operations on
these tables need to be fast enough.
Coming to your question of a DR with primary not in FORCE LOGGING
mode, is perfectly ok, if the management expectations are properly
set.
We just need to make sure that NOLOGGING operations performed in a
day/business cycle are well documented. Also the tables involved in
these operations are identified in advance. If there is a predefined
pattern for NOLOGGING operations that would also help.
Management should be notified that any operations performed on these
tables is unrecoverable and there is no DR for that.
Setup the standby normally as we would do for any other NORMAL
database. MRP process/ manual recovery process will apply archive logs
normally and mark all data blocks identified with nologging operations
are marked corrupted on standby database.
Run DBV on all data files periodically at standby site and sync up
those files manually ( just copy those files to standby site and
bounce the standby instance) once every few days. This interval can be
decreased depending on the business requirement and hardware/network
resources availability.
During all this process entire data that doesn't involve NOLOGGING is
still secure and applications depending on those information will
still work in case of switchover/fail over. Any operation on the
NOLOGGING data will result in "corrupted datablock" errors.
This process involves so much of manual work. This might not be a
perfect solution, but this works.
HTH,
Ravi.M
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