Solutions/Advanced Solutions/High Availability/
OS Clustering Solutions
OS Clustering Solutions
High availability plays a very key role for mission critical databases to maintain the uptime of the business applications. Operating System (OS) clustering solutions are most common HA solutions used in decades when there were no Database level clustering options available to achieve High Availability.
This is old way typically have 2 nodes (Primary/Secondary) that Secondary node always be in idle (unusable) state where data resides on Shared common storage between the nodes.
OS Cluster Cost/Risk Factors :
- OS Cluster Cost/Risk Factors :
- Shared – SAN is mandatory that results high cost – @ as per the vendor costing.
- Hardware – 2 nodes with all required HA components – @ as per the vendor costing.
- SAN shared storage with RAID mirroring – @ as per vendor costing.
- The Data is written common shared disk where one of the nodes is active at a time.
- The second node resides in idle (Unusable) state until Primary Node goes down.
- Data is at risk if the shared disk doesn’t get mounted which may lead to higher downtime.
- Failover Drills mandatory at frequent intervals to make sure the Second node brings the DB up when Primary node goes down.
- Any disk storage corruption on shared will bring total downtime where backups becomes only options for recovery resulting towards high RPO which based upon the size of the Database.
- No adequate Hardware resources utilization for secondary shared node
