RAC Archives - ASRblogger

Oracle RAC Startup Architecture

When troubleshooting an Oracle Real Application Clusters environment, understanding the startup sequence of cluster components is extremely important. Many issues during node boot, cluster startup or database availability can be…

Anish Kumar March 1, 2026No Comments

Oracle RAC

Voting Disk in Oracle RAC

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…

asrblogger February 18, 2026No Comments

Oracle RAC

Oracle Local Registry (OLR) in RAC

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…

asrblogger February 18, 2026No Comments

ASM DataGuard Oracle

Approach for Troubleshooting Oracle Database Unavailability in a Production Environment

Quickstart When an Oracle Database becomes unavailable in a production (PRD) environment, troubleshooting should follow a structured and non-destructive approach to preserve evidence and avoid data loss. 1. Capture the…

Anish Kumar January 29, 2026No Comments

DataGuard Oracle RAC

Resizing redo logs and standby Redologs in Dataguard

IN PRIMARY DATABASE :- 1) Check Instance details :- select status,instance_name,database_role from v$database,v$instance; ------------------------------------------------------------------------------------------------------------------------------------ 2) Check redo log and standby redo log size in Primary and standby :- Redo log…

asrblogger March 22, 2025No Comments

Core DBA DataGuard Oracle

Command to Check Archivelog Size

Oracle databases maintain a detailed history of all changes made to the database through archived redo logs, commonly known as archivelogs. These archivelogs are crucial for data recovery and are…

asrblogger July 9, 2024No Comments

Oracle RAC

Split Brain Syndrome in RAC

Where two or more instances attempt to control a cluster database. Each node in this cluster are interconnected through private interconnect and end users connects to cluster through public network.…

asrblogger October 21, 2023No Comments

Oracle RAC

Oracle Single Client Access Name (SCAN)

Single Client Access Name (SCAN) is a feature used in Oracle Real Application Clusters environments that provides a single name for clients to access any Oracle Database running in a…

asrblogger August 29, 2023No Comments

Oracle RAC

Prerequisite check “CheckActiveFilesAndExecutables” failed.

While trying to rollback the conflicting patch 18893947 applying patch 21967332 $ opatch rollback -id 18893947 Oracle Interim Patch Installer version 12.2.0.1.11 Copyright (c) 2018, Oracle Corporation. All rights reserved.…

asrblogger August 12, 2023No Comments

Interview Questions Oracle RAC

Oracle Clusterware Startup Sequence

What is Oracle Clusterware – RAC ? Oracle Clusterware enables servers to communicate with each other, so that they appear to function as a collective unit. This combination of servers…