Voting disks manage information about node membership. Each voting disk must be accessible by all nodes in the cluster for nodes to be members of the cluster1. You can store OCR and voting disks on Oracle Automatic Storage Management (Oracle ASM)2. If it is stored in ASM, no need to configure manually as the files … Read more
Oracle Clusterware includes three components: voting disks, Oracle Cluster Registry (OCR), and Oracle Local Registry (OLR). ■ Voting disks manage information about node membership. Each voting disk must be accessible by all nodes in the cluster for nodes to be members of the cluster. ■ OCR manages Oracle Clusterware and Oracle RAC database configuration information. … Read more
Enqueues are locks that coordinate access to database resources. This event indicates that the session is waiting for a lock that is held by another session. The V$EVENT_NAME view provides a complete list of all the enq: wait events. TM enqueue: The most common reason for waits on TM locks tend to involve foreign key … Read more
This wait indicates that we are waiting for a read operation which reads a number of contiguous blocks from disk. In most cases this indicates that there is some form of full scan (index fast full or full table scan) involved. This event signifies that the user process is reading buffers into the SGA buffer … Read more