Minimizing downtime with Multi-AZ

There are a number of instances where ElastiCache (Redis OSS) may need to replace a primary node; these include certain types of planned maintenance and the unlikely event of a primary node or Availability Zone failure.

This replacement results in some downtime for the cluster, but if Multi-AZ is enabled, the downtime is minimized. The role of primary node will automatically fail over to one of the read replicas. There is no need to create and provision a new primary node, because ElastiCache will handle this transparently. This failover and replica promotion ensure that you can resume writing to the new primary as soon as promotion is complete.

See Minimizing downtime in ElastiCache (Redis OSS) with Multi-AZ, to learn more about Multi-AZ and minimizing downtime.