Comment on What does the 3-2-1 rule look like for you?
CrazyLikeGollum@lemmy.world 2 weeks agoI don’t think this meets the definition of 3-2-1. Which isn’t a problem if it meets your requirements. Hell, I do something similar for my stuff. I have my primary NAS backed up to a secondary NAS. Both have BTRFS snapshots enabled, but the secondary has a longer retention period for snapshots. (One month vs one week). Then I have my secondary NAS mirrored to a NAS at my friends house for an offsite backup.
This is more of a 4-1-1 format.
But 3-2-1 is supposed to be:
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Three total copies of the data. Snapshots don’t count here, but the live data does.
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On two different types of media. I.e. one backup on HDD and another on optical media or tape.
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With at least one backup stored off site.
tburkhol@lemmy.world 2 weeks ago
I’ve always understood 2 as 2 physically different media - i.e., copies in different folders or partitions of the same disk is not enough to protect against failure of that disk, but a copy on a different disk does. Ideally 2 physically different systems, so failure/fire in the primary system won’t corrupt/damage the backup.
Used to be that HDDs were expensive and using them as backup media would have been economically crazy, so most systems evolved backup media to be slower and cheaper. The main thing is that having /home/user/critical, /home/user/critical-backup, and /home/user/critical-backup2 satisfies 3 copies, but not 2 media.