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Multiaz

MultiAz Instance Deployment

  • Replication is at storage level.
  • Replication is synchronous.
  • Database access is through database CNAME which points to primary instance
  • All reads and writes happen from primary instance
  • Backups & Snapshots happen from StandBy
  • When failover happens, database CNAME points to standby. Now it becomes Primary.This takes 60 to 120 seconds. Hence this switchover can have some downtime
  • There is only 1 standby replica
  • MultiAZ mode can be only within the same region

MultiAZ Cluster Deployment

  • Can replicate to one writer & 2 readers. The readers are in different AZs. This mode can have only 2 Readers while Aurora can have more
  • Replication between Writers & Readers is Synchronous
  • Data written to a Writer is confirmed to be committed when atleast 1 reader confirms replication
  • Each instance has its own storage
  • The end points available are
    • Cluster Endpoint which points to writer. It can be used for Reads, Writes & Administrative functions
    • Reader End Point points to the reader instances
    • Instance End Points point to each of the instances within the cluster
  • This runs on much faster hardware. Any writes are first written on to local NVME SSD Storage & then flushed to EBS
  • Replication is done through Transaction Logs
  • Failover can happen in upto 35s. Additional time is required to apply transaction logs to reader nodes