Data availability and protection

In a distributed relational database environment, data availability not only involves protecting data on an individual server in the network, but also ensuring that users have access to the data across the network.

The iSeries™ server provides the following array of functions to ensure that data on servers in a distributed relational database network is available for use:

• Save/restore
• Journal management and access path journaling
• Commitment control
• Auxiliary storage pools
• Checksum protection
• Mirrored protection and the uninterruptible power supply

While the system operator for each server is typically responsible for backup and recovery of that server's data, you should also consider aspects of network redundancy as well as data redundancy when planning your strategy to ensure the optimum availability of data across your network. The more critical certain data is to your enterprise, the more ways you should have to access that data.

• Recovery support for a distributed relational database
  Failures that can occur on a computer server are a server failure (when the entire server is not operating); a loss of the site due to fire, flood, or similar catastrophe; or the damage or loss of an object. For a distributed relational database, a failure on one server in the network prevents users across the entire network from accessing the relational database on that server.
• Network redundancy considerations for a distributed relational database
  Network redundancy provides different ways for users on the distributed relational database network to access a relational database on the network.
• Data redundancy in your distributed relational database network
  Data redundancy in a distributed relational database also provides different ways for users on the distributed relational database network to access a database on the network.