SQL Server

SQL Server Always On

Always On is not the default answer. It is the right answer when the business has named how much data it can lose and how long it can be down, and a simpler failover cannot meet those numbers.

When an availability group is justified

An availability group adds replicas, quorum and a failover you have to rehearse. Standard edition and Enterprise edition do not offer the same thing. We match the design to the edition you already license instead of assuming Enterprise features.

Clustering, log shipping and the rest of the HA/DR choices are compared on high availability and disaster recovery. If the real worry is a restore in another building, read disaster recovery before you buy a second replica.

Questions that decide the design

  • How many minutes of data can the business lose
  • How long can the application be down
  • Standard or Enterprise edition
  • One site or two
  • Who fails the group over, and has that been practiced

Talk through Always On before you build it

Edition, number of sites, and the outage you are trying to survive. We will say if an availability group is the right tool.