topic Re: Adding oracle instances on RHEL cluster in Operating System - Linux

Adding oracle instances on RHEL cluster

Manoj P.U. — Tue, 11 Jan 2011 18:25:34 GMT

Hello,

I am trying to configure multiple oracle instances in RHEL cluster.

Please find the attached cluster.conf I am trying with. The problem with this configuration is rgmanager service startup process stops after starting the 1st oracle instance.

There is no error message in the message file.

Any help would really easy my day.

Thanks and Regards,
Manoj

Re: Adding oracle instances on RHEL cluster

Zinky — Tue, 11 Jan 2011 19:08:31 GMT

Do you use Conga to manage your RHC Cluster?

Trust me -- it is easier to do it there. It has templates for Oracle as a service.

Re: Adding oracle instances on RHEL cluster

Manoj P.U. — Wed, 12 Jan 2011 12:46:41 GMT

Hi,

I have managed to get multiple oracle instances running in RHEL cluster.

Attached cluster.conf in which I have mentioned two separate startup scripts (customised oracledb.sh script)for oracle instances.

Now I am experiencing problem in enabling raw devices in during service failover. After service(volume group)failover, I had to issue "service rawdevices restart" command to map the raw devices.

Is there any way I can automate this with the help of cluster?

Thanks & Regards,
Manoj

Re: Adding oracle instances on RHEL cluster

Zinky — Wed, 12 Jan 2011 14:36:46 GMT

By raw devices -- do you mean ASM or does your database actually USE RAW devices?

You'd really have been better off using ASM IMHO but I digress.

since the raw device mappings is independent of the cluster, your raw device script should really be run once at each node's startup.

chkconfig rawdevices on

Cheers.

Re: Adding oracle instances on RHEL cluster

iinfi1 — Wed, 12 Jan 2011 20:09:52 GMT

hi all,

sorry for poking my nose here ... probably got nothing for the poster as such.
jus curious about a couple of things. why do people use a OS cluster like a red hat cluster suite or a suse cluster when Oracle has a clusterware for itself and there is Oracle enterprise linux as well.
is it to save cost of RAC licensing?
dont want to go into a OS war, but you would not get that load balancing which RAC offers isnt it?
how would you actually install two Oracle instances on RHCS cluster.

Would you have two Oracle HOMEs (similar to RAC) on the two nodes and depending on the node on which the database is running the instance name would change?
hmm .. probably the above works in RAC scenario.
But here incase of OS cluster you would have jus one Oracle HOME in a common storage partition moving from one node to the other incase of a failover.
does Oracle support this?

Re: Adding oracle instances on RHEL cluster

Zinky — Wed, 12 Jan 2011 20:43:50 GMT

Simple Failover Cluster Amigo...(active/passive they call it?)

RAC is a bit pricey and there are apps wherein HA means a simple ability to failover with minimal "downtime".

But seriously -- with Virtual Machines being able to float from Physical Server to another or from one CLOUD to ANOTHER Live -- who needs clustering at the OS level?

I still do cluster however between Virtual Servers that are on Different HA-Clouds/Hypervisors.... Just for Uber HIGH AVAILABILITY...

Re: Adding oracle instances on RHEL cluster

iinfi1 — Thu, 13 Jan 2011 08:39:12 GMT

thank you.

Even if we use VMs, we will have to setup an OS cluster on CentOS/RHEL/VMWare-HA between the hosts, isnt it?
Can VMs move from one machine to the other or in cloud without a OS cluster?

thanks again

Re: Adding oracle instances on RHEL cluster

Matti_Kurkela — Thu, 13 Jan 2011 14:56:37 GMT

If you're using Oracle 10g R2 or later, setting up /dev/raw devices is no longer necessary: Oracle will automatically open any Linux block devices using the O_DIRECT flag, which results in exactly the same effect as using the raw device would give you.

The /dev/raw devices are a legacy compatibility feature, for older applications that aren't programmed to use O_DIRECT.

The O_DIRECT feature has existed since RHEL 2.1; Oracle started using it in version 10g R2.

http://www.redhat.com/magazine/013nov05/features/oracle/
http://www.dba-oracle.com/art_orafaq_oracle_direct_io.htm
http://www.puschitz.com/TuningLinuxForOracle.shtml#UsingRawDevicesForOracleDatabases
http://www.puschitz.com/TuningLinuxForOracle.shtml#UsingBlockDevicesForOracle10gRelease2InRHEL4

MK

Re: Adding oracle instances on RHEL cluster

Zinky — Thu, 13 Jan 2011 15:05:33 GMT

"Even if we use VMs, we will have to setup an OS cluster on CentOS/RHEL/VMWare-HA between the hosts, isnt it?"

It is your choice.

In my case, even IF I cam able to move a Virtual Linux DB server on vMware or KVM live from one Physical Server to another -- there is still that possibility that the HA vMware/KVM cluster/cloud "COULD" Break -- hence the reason for additionally clustering the Virtual Linux DB Server -- for the BEST in high availability that can withstand:

- hardware failure
- accidents
- minimise effect of maintenance

But geneally - these days, people just have so much trust in there vSPhere anor KVM cluster/cloud that clustering (in a tradisional fashion) is becomin less popular. People still do RAC Virtual DB servers though -- for performance and scaleability reasons though.

Cheers!

Re: Adding oracle instances on RHEL cluster

Manoj P.U. — Sun, 16 Jan 2011 11:18:51 GMT

Hi All,
Thanks for your reponse.

Finally I could setup the RHEL cluster with raw logical volume and multiple oracle instances.

I do agree that there is no significant adavantage keeping raw volumes. But I had to configure raw volume since dba insisted me to have database + asm + raw volume.

Resolution:
multiple oracle instances -
I have customised the script /usr/share/cluster/oracledb.sh and created three copy of the script, each for different oracle instances.

Raw logical volumes-

Configured raw logical volume with the help of udev configuration file /etc/udev/rules.d/60-raw.rules.

Thanks again for your response and advice.

Manoj PU

Re: Adding oracle instances on RHEL cluster

Manoj P.U. — Sun, 16 Jan 2011 11:19:29 GMT

Thanks you

Re: Adding oracle instances on RHEL cluster

nasir9903 — Wed, 04 May 2011 05:12:16 GMT

Manoj i am trying to do the simmilar setup of adding one more oracle instance to my existing rhel cluster.can you plz help me out by sharing the config files and other details
thanks in advance