Re: RAC problem, TAF in primary/secondary role?
- From: tomi wijanto <restomi_w@xxxxxxxxx>
- To: oracle-l@xxxxxxxxxxxxx
- Date: Fri, 22 Oct 2004 01:55:37 -0700 (PDT)
Hi,
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.
regards,
tomi
--- Jonathan Lewis <jonathan@xxxxxxxxxxxxxxxxxx>
wrote:
>
>
> 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
>
> http://www.jlcomp.demon.co.uk/faq/ind_faq.html
> The Co-operative Oracle Users' FAQ
>
> http://www.jlcomp.demon.co.uk/seminar.html
> Optimising Oracle Seminar - schedule updated Sept
> 19th
>
>
>
>
>
> ----- Original Message -----
> From: "tomi wijanto" <restomi_w@xxxxxxxxx>
> To: "oracle-l" <oracle-l@xxxxxxxxxxxxx>
> 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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