High Availability Clustering and Business Continuity
Database HA and DR Terms
High availability is the ability of a system to be able to run continuously without interruption.
What is uptime?
Uptime is the amount of time that a system remains up-and-running successfully.
What is downtime?
Downtime is when a system is not operating normally due to a point of failure in the environment or other issue.
What is five 9s high availability?
Many organizations shoot for this statistical mark of achieving 99.999% uptime. This means experiencing no more than five minutes and fifteen seconds of downtime per year.
What is high availability clustering software?
High availability clustering software allows organizations to interconnect a network of server nodes to achieve a level of redundancy. If a point of failure is identified, HA clustering software takes prompt reactive action to make sure workloads continue to be hosted successfully within an environment. The best high availability software also takes proactive action to keep workloads running in their best execution venues to stay performant and meet SLA requirements.
What is smart high availability clustering software?
Smart High Availability (HA) is the convergence of high availability and software-defined perimeter technology. Along with the standard catalog of high availability functionality, “Smart” HA integrates built-in zero trust security capability—connecting all nodes with secure, encrypted, zero trust network access tunnels. Additionally, smart HA software unlocks unified management for Windows, Linux, instances, and containers to be a one-stop-shop clustering technology for database applications like SQL Server.
What is failover?
Failover is the act of taking a workload and rehosting it on a new node to ensure ongoing operation. This action is done primarily in response to detected outages or inadequate performance levels.
What is disaster recovery?
Disaster recovery is the ability of an organization to restore natural process and recover after a catastrophic downtime event such as natural disaster, cyber breach, or something else.
What is a stretch cluster?
A stretch cluster is a multi-node cluster in which one of the host nodes exists in a different geographic location and/or subnet from the rest. This is a best practice when setting up disaster recovery for the purpose of having an isolated backup if a whole physical hosting environment is compromised.