Environment resilience can be broken up into two sections, the physical environment, and the logical environment. The physical environment, which is really part of single system availability, focuses on things such as hardware redundancy, network topology, power infrastructure, and cooling capabilities. The logical environment is the application hosting and execution environment. It includes things like system settings, user profiles and system attributes that allow the user to run the application on multiple servers.
- Physical Environment
- The physical environment consists of single system availability features and the utilities required to adequately maintain a computer operating environment. These single system availability features are key to maintain a high availability environment. The system has many features to protect from hardware failures. The first component to protect is the disk subsystem. RAID 5, RAID 6, RAID 10, and disk mirroring are all offered protection mechanisms. One of these protection mechanisms is basically a requirement for any business.
- Another component that should be protected is the network. This includes both redundant network adapters on the system, and multiple paths through the network over redundant network hardware for users and systems to use for communication.
- The physical environment also includes the utility services needed to run the computer room. The system provides the capability to run on dual power cords. This means that each tower or rack has two power cables to plug into two different power outlets. This allows a computer room to have different breaker panels feeding each rack or tower. Due to the nature of public utility power, strong consideration should be given to protecting computer room power by an uninterruptible power supply or a generator.
- Other considerations must be given to the physical room characteristics such as heating, cooling, air humidity, and air purity.
- Logical Environment
- The logical environment is the application runtime environment. This consists of the system attributes, system values, network configuration attributes, work management configuration and user profiles. These things must be the same for the application environment to operate the same way on the backup system as it does on the primary production system. Keeping these logical environmental values consistent across multiple systems can be done though a cluster administrative domain, logical replication, or a well defined manual process.