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Re: RAC problem, TAF in primary/secondary role?

From: tomi wijanto <>
Date: Fri, 22 Oct 2004 01:55:37 -0700 (PDT)
Message-ID: <>


i have tested the primary / secondary role, and i found some differences when using TAF.

For example when NOT using active_instance_count, first i connect to instance A, and then i shutdown instance A. From the same session, i check that it was failed over to instance B (select * from v$instance). Then i startup instance A and shutdown instance B. It also failed over back to instance A.

But when i use prim/second role, failover didn't worked. I always get error message 'shutdown in process' or 'disconnected'.
So, does TAF not work in this kind of setting? The only failover that is success is for connection/logon time.


> The Global Resource Directory is statically
> hashed between all available nodes. (Although
> a cunning implementation allows it to be gradually
> re-hashed when node counts change).
> This means that (on average) half the global cache
> resources for your tablescan will be mastered on
> the wrong node, so Oracle will need to make cross
> instance calls to acquire the relevant gc locks.
> The primary/secondary implementation is a very
> special case which puts the entire GRD onto just
> one node, which is the node you must make available
> as public node. All the GC operations will be
> local,
> which will have a significant effect on the
> tablescan.
> The secondary node can still be used (e.g. for
> large-scale
> maintenance) but every operation will have always be
> using remote resources, so the instance will run
> more
> slowly than you might expect.
> Regards
> Jonathan Lewis
> The Co-operative Oracle Users' FAQ
> Optimising Oracle Seminar - schedule updated Sept
> 19th
> ----- Original Message -----
> From: "tomi wijanto" <>
> To: "oracle-l" <>
> Sent: Friday, October 22, 2004 4:55 AM
> Subject: Re: RAC problem, is gc_files_to_locks is
> needed?
> Hi, thanks for the reply..
> i only change tnsnames to disable load balancing and
> enable failover, just like you said on second
> option.
> All instances are up.
> Your third option is very interesting. What is the
> differences from cache fusion perspective between
> primary/secondary role and my way, assume all
> clients
> always connect to the first instance in their
> tnsnames?
> regards,
> tomi

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Received on Fri Oct 22 2004 - 03:51:13 CDT

Original text of this message