[SPIKE] Determine Backup Conventions #5428
Description
Backup Conventions
As a general reminder, please update any docs after decisions are made.
A Little Context
We backup everything every two hours during work hours (7am to 7pm or so). The files are stored in directories named month-day-hour, so they end up overwriting each other after a year has passed. Thus, the bucket grows only a little bit in size once the whole year has been stored. That is a downright silly amount of data.
Retention
How long should we realistically expect to need a backup? If an issue is found we'll use the most recent "good" backup, which may be as little as a few hours old. Our backups lose value rapidly, since during a restore users will lose all progress made since the backup. Going back more than... A week? Is detrimental.
Perhaps we keep all backups in the last week, one a day for the month, and none before that. But storage is cheap, so perhaps we could/should keep a full month.
Deletion
How often should we delete backups? Perhaps on its own action every weekend. Perhaps as an addition to the regular backups.
Naming
Backups folders are named month-day-hour. If we are constantly creating and deleting backups properly, we can instead timestamp them. YearMonthDay-hour, I'd suggest.
Requirements to Consider
Does our ATO say anything about backup cadence or retention? Is there an ADR that discusses? It would be good to do a little discovery as part of these conversations.