Comment by paulryanrogers
Comment by paulryanrogers 10 months ago
You have to pay 2x for multi-AZ or you get downtime for upgrades. And DB major version upgrades require manual effort unless you want to roll the dice on their new blue-green feature, which can take hours to fail or finish cutting over.
> 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.