Dated: 12-11-2024
Ch02 High Availability and Redundancy case Study
- Mid-sized enterprise
- 3000 total staff
- 2000 IT users
- 30 IT team
- One DC, one secondary (regional) data center (warm site & backup site), and one DR site
- 99.9 % uptime designed
It Setup
- Oracle ERP system
- Sharepoint portal for workflow automation
- Head office in Karachi
- Primary DC in Karachi (hosted with 3rd party)
- DR site in Lahore (hosted with 3rd party)
- Secondary DC in ISB
Primary Dc
- Fully redundant (HA) design for network, systems, and storage
- Cisco HA (active-standby)
- Oracle cluster technology for servers and DBs (active-active)
Secondary Dc (ISB)
- All network, systems, and storage backups maintained here (also mirrored in DR)
- Regional servers (AD, file servers, etc)
- Test & staging environment here (segregated from main DC)
- Office working space
Dr Site
- Bare minimum HA (as DR site) for network, systems, and storage
- Mirror of all backups from secondary site maintained here
- Office working space
- Some additional computing capacity (minimum for unforeseen events)
- All critical systems and devices maintained in active mode (hot) for immediate DR failover
- Data maintained as per org RTO/RPO for immediate utility
- Monthly DR testing/drill
Backup Strategy
- Primary backup at secondary DR site
- Mirror at DR site
- For critical systems: monthly full backup, daily incremental backup
- For critical network devices: weekly full backup; backups based on change