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Changing parameter in RAC node one by one [message #457187] Fri, 21 May 2010 11:59 Go to next message
nadvi
Messages: 46
Registered: May 2006
Location: Canada
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I want to change the following log_buffer parameter in two node RAC cluster.
alter system set log_buffer=5242880 scope=spfile;

To ensure availability, how the command can be issued on each node avoiding any downtime of both the nodes. Means, reflecting the change in one node first after finishing the tasks, do the same on another node.

Thanks.
Re: Changing parameter in RAC node one by one [message #457188 is a reply to message #457187] Fri, 21 May 2010 12:13 Go to previous messageGo to next message
Michel Cadot
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You can use "sid" option to change the parameter in only 1 node:
alter system set log_buffer=5242880 scope=spfile sid='sid1';

But as log_buffer is a static parameter you can change it for all instances, it will only be taken in account at the next restart and does not impact currently active instance.

Regards
Michel



Re: Changing parameter in RAC node one by one [message #457189 is a reply to message #457188] Fri, 21 May 2010 12:19 Go to previous messageGo to next message
nadvi
Messages: 46
Registered: May 2006
Location: Canada
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Thanks Michel. Concept is clear now Smile
Re: Changing parameter in RAC node one by one [message #457955 is a reply to message #457188] Wed, 26 May 2010 09:33 Go to previous messageGo to next message
nadvi
Messages: 46
Registered: May 2006
Location: Canada
Member

Hi Michel,

I have another relevant question.

Is it obvious that, shutting down one node of RAC would disconnect all the connected session in node1?
while node 1 is down, reconnecting to RAC establishes the connection to node2 (load balance is ON)

But, is there any way to avoid disconnection of connected sessions from NODE1 while shudown immediate command executed in node1?

Thanks
Re: Changing parameter in RAC node one by one [message #457967 is a reply to message #457187] Wed, 26 May 2010 10:11 Go to previous messageGo to next message
mkounalis
Messages: 146
Registered: October 2009
Location: Dallas, TX
Senior Member
If you shut down an instance, all connections to that instance will get disconnected. If you have TAF configured at your client, the connections will reconnect to a surviving node. Any select statements in progress will complete, but any uncommitted dml running will have to be re-executed as the transaction will have been rolled back. I would look at the RAC concepts manual for details at docs.oracle.com. You may want to enable FAN via ONS to your client to handle node failures or planned node outages. The client is responsible for handling database connections - there is no automagical movement of connections between rac nodes in the case of a failure or a shutdown.
Re: Changing parameter in RAC node one by one [message #457970 is a reply to message #457967] Wed, 26 May 2010 10:15 Go to previous messageGo to next message
Michel Cadot
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Yes! pretty good answer that summarize the whole and complex stuff in few sentences. ./fa/2115/0/

By the way, TAF is Transparent Application Failover.

Regards
Michel
Re: Changing parameter in RAC node one by one [message #457972 is a reply to message #457967] Wed, 26 May 2010 10:17 Go to previous message
nadvi
Messages: 46
Registered: May 2006
Location: Canada
Member

Thanks Smile really nice reply
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