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.
While it’s true that “It depends on your business needs”, most often I’ve seen backup schemes which work on a minimum of a daily backup of most data. For example, on a larger, busier system, it might have a full backup done over the weekend when the system isn’t as busy and therefore has a lower business impact. Then daily differential backups are done each night. For smaller systems, it might just be a full backup of critical data every night.
For highly active, critical SQL databases, I’ve also seen this extended where the a full backup was done of the database weekly, with differential backups done nightly and transaction log backups done every 15 minutes. This obviously had full transactional logging turned on for the critical databases.
As a concrete example, on my home “server” (desktop with delusions of grandeur), the main data partition is running on ZFS with snapshots taken every 15 minutes, hourly, daily, weekly and monthly. The 15 min. snapshots are kept for an hour. Hourly snapshots are kept for 24 hours. Daily snapshots are kept for 31 days. Weekly snapshots are kept for 8 weeks. Monthly snapshots are kept for 12 months. There’s a bit of overlap in the daily and weekly schedules, as those are most likely to cover my arse from an “oops” factor.
The downside of the snapshot setup is that it doesn’t provide disaster recovery. And, I’ll admit, for my home stuff I haven’t gotten around to sorting this out. Ideally, I should be taking a weekly backup, compressing and encrypting it and pushing it to a cloud service somewhere. Laziness has meant that hasn’t been done yet.
Most VMs backed up daily, depending on how vital then stored for anything from 3 days - 30 days. Few machines are backed up 3 times a week cause they’re tests servers and we’ll take snapshots as and when they’re getting actively used. Finally a couple of machines are backed up 6 hourly for data relevancy.
Everything replicated to a second backup server off-site and have a hardened repo for immutable backups.