I was wondering how often does one choose to make and keep back ups. I know that “It depends on your business needs”, but that is rather vague and unsatisfying, so I was hoping to hear some heuristics from the community. Like say I had a workstation/desktop that is acting as a server at a shop (taking inventory / sales receipts) and would be using something like timeshift to keep snapshots. I feel like keeping two daily and a weekly would be alright for a store, since the two most recent would not be too old or something. I also feel like using the hourly snapshots would be too taxing on a CPU and might be using to much disk space.

  • @conorabAEnglish
    1•6 months ago
    • Personal and business are extremely different. In personal, you backup to defend against your own screwups, ransomware and hardware failure. You are much more likely to predict what is changing most and what is most important so it’s easier to know exactly what needs hourly backups and what needs monthly backups. In business you protect against everything in personal + other people’s screwups and malicious users.
    • If you had to setup backups for business without any further details: 7 daily, 4 weekly, 12 monthly (or as many as you can). You really should discuss this with the affected people though.
    • If you had to setup backups for personal (and not more than a few users): 7 daily, 1 monthly, 1 yearly.
    • Keep as much as you can handle if you already paid for backups (on-site hardware and fixed cost remote backups). No point having several terabytes of free backup space but this will be more wear on the hardware.
    • How much time are you willing to lose? If you lost 1 hour of game saves or the office’s work and therefore 1 hour of labour for you or the whole office would it be OK? The “whole office” part is quite unlikely especially if you set up permissions to reduce the amount of damage people can do. It’s most likely to be 1 file or folder.
    • You generally don’t need to keep hourly snapshots for more than a couple days since if it’s important enough to need the last hours copy, it will probably be noticed within 2 days. Hourly snapshots can also be very expensive.
    • You almost always want daily snapshots for a week. If you can hold them for longer, then do it since they are useful to restoring screwups that went unnoticed for a while and are very useful for auditing. However, keeping a lot of daily snapshots in a high-churn environment gets expensive quickly especially when backing up Windows VMs.
    • Weekly and monthly snapshots largely cover auditing and malicious users where something was deleted or changed and nobody noticed for a long time. Prioritise keeping daily snapshots over weekly snapshots, and weekly snapshots over monthly snapshots.
    • Yearly snapshots are more for archival and restoring that folder which nobody touched forever and was deleted to save space.
    • The numbers above assume a backup system which keeps anything older than 1 month in full and maybe even a week in full (a total duplicate). This is generally done in case of corruption. Keeping daily snapshots for 1 year as increments is very cheap but you risk losing everything due to bitrot. If you are depending on incrementals for long periods of time, you need regular scrubs and redundancy.
    • When referring to snapshots I am referring to snapshots stored on the backup storage, not production. Snapshots on the same storage as your production are only useful for non-hardware issues and some ransomware issues. You snapshots must exist on a seperate server and storage. Your snapshots must also be replicated off-site minus hourly snapshots unless you absolutely cannot afford to lose the last hour (billing/transaction details).