Re: Questions consolidating databases onto RAC Cluster
Date: Wed, 27 Apr 2016 23:06:59 +0200 (CEST)
Message-ID: <1043982355.929571.1461791219130.JavaMail.open-xchange_at_app04.ox.hosteurope.de>
Hey Chris,
i usually agree with Tom, but IMHO his statement "The only correct number of instances per host is - one. If you have more than one instance per host, you cannot prevent one instance from consuming all of a given resource - causing a virtual outage of the other instance" is out-dated.
He is still right that you can not consolidate several hundreds of instances on one host as the OS needs to handle the amount of processes, but two databases on RAC should be no issue at all - especially with a current utilization of 10%.
Nowadays you also can really "cage" the instance with cgroups for example and limit memory with event like 10261 or with official documented parameters in 12c. The only part that could not be "caged" is I/O unless you move to Exadata + resource manager.
Best Regards
Stefan Koehler
Freelance Oracle performance consultant and researcher
Homepage: http://www.soocs.de
Twitter: _at_OracleSK
> Chris Taylor <christopherdtaylor1994_at_gmail.com> hat am 27. April 2016 um 22:13 geschrieben:
>
> After doing some research, it appears that common wisdom is to NEVER have 2 different RAC databases sharing the same cluster.
>
> For example:
> 2 Node RAC with more than one RAC DB
>
> Is this still true?
> Reference: https://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:1855800700346081917
>
> If you have a RAC DB on 2 nodes, but the nodes are only 10% utilized, is the only best option really to migrate the schemas into the existing RAC
> DB instead of adding separate RAC DBs to the existing cluster?
>
> Is there some other option here that I'm missing to take advantage of the spare resources on the RAC cluster hosts? (Other than 12c and
> multi-tenant)
>
> Chris
-- http://www.freelists.org/webpage/oracle-lReceived on Wed Apr 27 2016 - 23:06:59 CEST