Clusterware Components

Clusterware Components are

1. OCR ( Oracle Cluster Registry )

2. VD ( Voating Disk )

3. OLR ( Oracle Local Registry )


1. OCR ( Oracle Cluster Registry ) :

* OCR contains information cluster configuration like how many Database,how many instances,how     many services and state of the services

* CRSCTL,SRVCTL,LSNRCTL will updates the information to the OCR whenever state the change     of instance,listener are other services

* when OCR corrupted we are not able to start the cluster

* every four hours it will take automatic bakup,if you want to take manually as you want

     $ocrnfig -export

* To check ocr file location

  $ocrconfig


2. VD ( Voating Disk ):

* VD contains information Node membership information,every 3o seconds each node will send a          meaasge or signal to vating disk,stateing that is alive.

* if it is not able to send a signal to VD, VD will send some messages or signals to node and it will initiate the node reboot.

* every four hours backup also taking along with OCR,

* if voating disk is corrupted we are not able to start the cluster.

* To check VD location

  $crsctl query css votedisk


3. OLR ( Oracle Local Registry ):

* OLR contains information that allow cluster processes to be started up with the  OCR being in the ASM storage system,since the asm file system is unavailable untill the grid processes are started up a  local copy of the contents of the ocr is required which is store din OLR

* OLR contains GRID_HOME,GRID_VERSION,GPNP PROFILE,local host name,active version,ocr latest backup and location,node name,ocr about ocr daily,weekly backup location.

* To check olr location
 $ocrconfig -local