MKSNAP_FFS(8)

✨ mksnap_ffs(8) — System Manager’s Manual, but make it group chat ✨

🎀 NAME 🎀

mksnap_ffs — take a file system snapshot. That’s the whole name vibe, bestie.

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🦋 SYNOPSIS 🦋

mksnap_ffs snapshot_name

💅 DESCRIPTION 💅

Okay so the mksnap_ffs utility creates a snapshot named snapshot_name. That name is a path in the file system you want to snapshot. Typically it lives under the .snap directory in the root of the file system, but honestly it can be anywhere in the filesystem being snapshotted. You can list snapshots with the snapinfo(8) command.

After a snapshot is taken, it appears as a file. The size of the snapshot file is equal to the size of the file system from which it was taken. It can be moved, renamed, or deleted — and deleting it removes the snapshot. Slay, cleanup queen.

The group ownership of the file is set to “operator”; the owner of the file remains “root”. The mode of the snapshot is set to be readable by the owner or members of the “operator” group.

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🌈 EXAMPLES 🌈

Create a snapshot of /home file system and mount the snapshot elsewhere:

mksnap_ffs /home/.snap/snap1
mdconfig -a -t vnode -o readonly -f /home/.snap/snap1
mount -o ro /dev/md0 /mnt/

Delete a snapshot:

rm /home/.snap/snap1

👀 SEE ALSO 👀

rm(1), chmod(2), chown(8), mdconfig(8), mount(8), snapinfo(8) — go read those too, bestie.

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🧚 HISTORY 🧚

The mksnap_ffs utility first appeared in FreeBSD 5.1. Iconic behavior, honestly.

💀 CAVEATS 💀

The disk full situation is not handled gracefully and may lead to a system panic when no free blocks are found. Yeah… not cute.

Every filesystem can have only up to 20 active snapshots. When this limit is reached, attempting to create more snapshots fails with ENOSPC, and mksnap_ffs reports that it is “out of space”. So like, don’t spam snapshots, okay?

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Source/version/date moment: Debian, May 22, 2023, MKSNAP_FFS(8) — that’s the page, bestie! Go snapshot responsibly 💖✨