limit-fs

FUSE filesystem that removes the oldest files whenever the used space reaches the set percentage.

You can use it in a no empty directory, anything you write in will be written in the underlying filesystem. After unmounting it all files remain in the unmounted directory.

How to use

Once limit-fs is installed running it is very simple:

limit-fs [FUSE options] [mount options] mountPoint

It is strongly recommended to run limit-fs as regular user (not as root). For this to work the mount point must be owned by the user.

To unmount the filesystem use fusermount -u mountpoint

Screencast

File-system specific options

You can specify the options:

long option	short option	default	description
--usage-limit=	-u	80	set the usage limit in percentage.
--help	-h		print help message
--version	-V		print version

Runtime mounting

limit-fs --usage-limit=90 /mnt/

Mounting automatically at boot time with fstab

Add the FS to the /etc/fstab file. For example take the line:

limit-fs   /mnt/tmpfs/limitfs	limit-fs	usage-limit=95,id=1000,gid=1000,user	0 0

Second part is the mount point which the limit-fs is mounted.

Next use limit-fs in the file system type.

Then comes the options usage-limit=95,uid=1000,gid=1000,user

Mounting automatically at boot time with systemd

The name of file for automatic mounting must reflect the mount point, to doesn't make a mistake use the command to compose the name:

$ systemd-escape -p --suffix=mount /path/to/mount/point
path-to-mount-point.mount

Substitute /path/to/mount/point with the correct mount point. If the mount point does not exist at the time of mounting, it is created.

1. Create the file to setup the mount itself

# cat > /etc/systemd/system/path-to-mount-point.mount <<EOF
[Unit]
Description=limit-fs

[Mount]
What=limit-fs
Where=/path/to/mount/point
Options=usage-limit=95,uid=1000,gid=1005,users
Type=limit-fs

[Install]
WantedBy=multi-user.target
EOF

2. Create the file to perform automatic mounting

# cat > /etc/systemd/system/path-to-mount-point.automount <<EOF
[Unit]
Description=Automount limit-fs

[Automount]
Where=/path/to/mount/point

[Install]
WantedBy=multi-user.target
EOF

3. Notify systemd there are some new files available

# systemctl daemon-reload

4. Enable the automount

# systemctl enable path-to-mount-point.automount

Installation from source

• Install dependences:

  • Fedora >= 27

    # dnf install m4 automake autoconf gcc fuse3 fuse3-devel
    

  • CentOS/RHEL/Fedora

    # yum install m4 automake autoconf gcc fuse fuse-devel
    

  • Debian

    # apt-get install m4 automake autoconf gcc fuse libfuse-dev pkg-config make
    

• Compile and install

  $ ./setup.sh
  $ ./configure
  $ make
  $ sudo make install