Saturday, April 3, 2010

11gR2 RAC , GRID infrastructure ASM ,vote ,ocr bla bla.... and a big confusion before you implement these.

11gR2 RAC , GRID infrastructure ASM :

Since I did my first implementation, I was interested in sharing

1) Why is VOTE and OCR inside ASM?

Storing the OCR and vote disk inside ASM eliminates the need for third party cluster and volume managers and also helps eliminate the complexity of managing separate disk partitions for the OCR in oracle clusterware installations.
Better manageability. and also Oracle WANT to SELL RAC with ASM ,....

2) How does cluster start as vote disk and OCR are inside ASM???

In 11GR2, every node has a local registry called OLR. OLR is created during the installation and by default its located under $GRID_HOME/cdata/.olr
This file actually facilitates the oracle cluterware to startup process when OCR and vote are inside ASM.

During the startup OLR is referenced to determine the exact location of the vote disks. This will facilitate the node to join the cluster. After the initial phase ASM is started and the processes that require full OCR can start and the clusterware startup process completes.

3) SAN and NAS.

I always assumed EMC sells only SAN . But they too have NAS storage.Since we prefer to have block storage for oracle database we opted SAN for oracle software and NAS for usual NFS.

Also good that now there is a EM plugin avaliable to monitor EMC disks.


Sandarsh Chavalmane