> You have to pay 2x for multi-AZ or you get downtime for upgrades.
Worse. In Single AZ deployments you get (short, but not that short or strongly bound) downtime for daily backups and when doing snapshots. Source:
- https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_...: "During the automatic backup window, storage I/O might be suspended briefly while the backup process initializes (typically under a few seconds). [...] For MariaDB, MySQL, Oracle, and PostgreSQL, I/O activity isn't suspended on your primary during backup for Multi-AZ deployments because the backup is taken from the standby. ",
- https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_...: "Amazon RDS creates a storage volume snapshot of your DB instance, backing up the entire DB instance and not just individual databases. Creating this DB snapshot on a Single-AZ DB instance results in a brief I/O suspension that can last from a few seconds to a few minutes, depending on the size and class of your DB instance.".
Not to mention that multi-AZ deployments incur extra transfer cost between zones - not between DB instances (this one is free, last time I checked), but between your compute deployments and DB instances, if your compute does not automatically follow the zone of the db host it talks to.
Worse. In Single AZ deployments you get (short, but not that short or strongly bound) downtime for daily backups and when doing snapshots. Source:
- https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_...: "During the automatic backup window, storage I/O might be suspended briefly while the backup process initializes (typically under a few seconds). [...] For MariaDB, MySQL, Oracle, and PostgreSQL, I/O activity isn't suspended on your primary during backup for Multi-AZ deployments because the backup is taken from the standby. ",
- https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_...: "Amazon RDS creates a storage volume snapshot of your DB instance, backing up the entire DB instance and not just individual databases. Creating this DB snapshot on a Single-AZ DB instance results in a brief I/O suspension that can last from a few seconds to a few minutes, depending on the size and class of your DB instance.".
Not to mention that multi-AZ deployments incur extra transfer cost between zones - not between DB instances (this one is free, last time I checked), but between your compute deployments and DB instances, if your compute does not automatically follow the zone of the db host it talks to.