Re: RAC + cluster waits

From: De DBA <>
Date: Wed, 19 Feb 2014 14:41:33 +1000
Message-ID: <>

Hi John,

I'm not very experienced with clusters, but I believe that most clusters nowadays run on ASM. If yours does, could the wait be ASM related? As you mention that the cluster is mature, and has been running (and presumably growing) for several years, perhaps the ASM instance now has reached the point where the SGA is beginning to fill up? In other words, perhaps the cause for the waits is not in the DB, but rather in the underlying cluster filesystem?

Just my 2c..


On 19/02/14 00:19, Fedock, John (KAM.RIC) wrote:
> Need some advice regarding cluster wait issues on a 3 node Linux Oracle system.
> Short question -- How can I determine what is causing recent cluster waits on our database?
> Long question -- We have a mature system that has been running well for several years. Recently some performance issues have started and they seem to be related to cluster wait events.
> It is easy enough to see what events are waiting for clustered waits, but not what is *causing* them to wait. When we are having issues, I may see several dozen session waiting for 2 or 3 seconds and then they clear up, then a few seconds later, it repeats. I have run several awrrpt and awrgrpt and cannot see anything obvious.
> It also seems like node1 is the one that has the session waiting.
> Any advice?
> Thanks all.
> John Fedock

Received on Wed Feb 19 2014 - 05:41:33 CET

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