High availability
High availability (HA) is the ability to remain available with no interruption to service during a system outage. Its purpose is to provide uninterrupted access to an application over a long time. It requires at least two servers running on different hardware. It optionally uses redundant hardware on each server and may run servers inside virtual machines that automatically and transparently move off failed hardware servers to working hardware. It also requires mechanisms to detect software or hardware failure as well as mechanisms to ensure that a failed server remains down so that it does not process data unexpectedly and create data inconsistencies. Lastly, it provides mechanisms to automatically fail over database software and notify client applications to reconnect to the proper running database server.
FairCom’s fall 2020 release provides integration with Linux and Windows OS failover solutions as well as its own database failover solution.
Disaster recovery (DR) is the ability to recover from a catastrophic regional failure in a few hours or a few days. Its purpose is to recover from a disaster by running an application in a different geographical region. This requires databases to be running in multiple data centers in different regions. The databases replicate data continuously from one region to another.
