FSFREEZE(8)

💖 fsfreeze — bestie edition (section 8, system admin girlies rise) 💖

okay so. fsfreeze is a lil command from the fsfreeze(8) manual, and she's here to do ONE thing and do it gorgeously: put your filesystem on pause. like, full ✨freeze✨ mode. let's get into it 🧊

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✨ NAME ✨

fsfreeze — suspend access to a filesystem (Ext3/4, ReiserFS, JFS, XFS)

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🌸 SYNOPSIS 🌸

fsfreeze --freeze|--unfreeze mountpoint

like that's it. that's the whole vibe. pick freeze or unfreeze, point her at a mountpoint, slay 💅

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🦋 DESCRIPTION 🦋

So fsfreeze suspends or resumes access to a filesystem. That's the whole personality.

What "freeze" actually means: it halts any new access to the filesystem and creates a stable image on disk. And why would you want that?? Because fsfreeze is intended to be used with hardware RAID devices that support the creation of snapshots. you want the snapshot to be of a nice calm frozen filesystem, not a chaotic one mid-write. it's giving ✨stability✨.

ngl though, if you're on device-mapper devices, you can literally skip all this. fsfreeze is unnecessary for device-mapper devices — because device-mapper (and LVM) automatically freezes a filesystem on the device when a snapshot creation is requested. it just does it for you, no cap. more deets live in the dmsetup(8) man page.

Now, the mountpoint argument? that's the pathname of the directory where the filesystem is mounted. And important: the filesystem must be mounted to be frozen (go check mount(8) if you need a refresher bestie).

Also a lil heads up 🙈: access-time updates are also suspended if the filesystem is mounted with the traditional atime behavior — that's the mount option strictatime, more info in mount(8).

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💅 OPTIONS 💅

• -f, --freeze — this one requests the specified filesystem to be frozen from new modifications. When you pick this, here's the whole tea: all ongoing transactions in the filesystem are allowed to complete, new write(2) system calls are halted, other calls which modify the filesystem are halted, and all dirty data, metadata, and log information are written to disk. And any process tryna write to the frozen filesystem? it will block, waiting for the filesystem to be unfrozen. it's just sitting there. patiently. like a bestie waiting outside the fitting room 🫶

also note (this one's a lil sneaky): even after freezing, the on-disk filesystem can contain information on files that are still in the process of unlinking. Those files will not be unlinked until the filesystem is unfrozen or a clean mount of the snapshot is complete. so like, they're ghost files, they're haunting, they're fine, don't worry about it 💀

• -u, --unfreeze — the un-freeze. used to un-freeze the filesystem and allow operations to continue. Any filesystem modifications that got blocked by the freeze are unblocked and allowed to complete. everyone's free, go off, do your writes ✨
• -h, --help — display help text and exit. classic. iconic. she's helpful.
• -V, --version — display version and exit. also iconic.

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🌈 FILESYSTEM SUPPORT 🌈

this command will work only if the filesystem supports freezing. As of 2016-12-18, the list includes: btrfs, ext2/3/4, f2fs, jfs, nilfs2, reiserfs, and xfs.

That list may be incomplete tho, since more filesystems keep getting support (they're evolving, main character energy fr).

If you're in doubt, the easiest way to know if a filesystem has support is to create a small loopback mount and test freezing it. little test drive. very demure, very mindful 🎀

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📝 NOTES 📝

This man page is based on xfs_freeze(8). giving credit where credit is due 💜

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👑 AUTHORS 👑

Written by Hajime Taira. legend behavior.

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🔗 SEE ALSO 🔗

mount(8)

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🐛 REPORTING BUGS 🐛

Found a bug? not the vibe but also pls tell someone. For bug reports, use the issue tracker at <https://github.com/util-linux/util-linux/issues>.

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⭐ AVAILABILITY ⭐

The fsfreeze command is part of the util-linux package, which you can download from the Linux Kernel Archive at <https://www.kernel.org/pub/linux/utils/util-linux/>. go get her 🦋

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💀 reminder bestie: fsfreeze without a mounted filesystem is a no. and freeze without unfreeze is just a filesystem in timeout. be kind, unfreeze her.

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okay that's the whole page, mwah 😘 this was util-linux 2.42.4, dated 2026-09-21, and that's the FSFREEZE(8) vibe check, passed with flying colors 💖✨🧚