How to Limit the Size of a Folder in Linux

Use the image file mounting method to limit the size of the folder in Linux.

Mount the image file to limit the size of the folder, and it can be easily unmounted when not needed.

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Mount

1. First, create a disk image file of the specified size

   dd if=/dev/zero of=/root/disk.img bs=2M count=512
   

   The input device used here is /dev/zero, which can provide unlimited characters. Here we create a 1GB disk image.

2. Mount the image file as a device

   losetup /dev/loop0 /root/disk.img
   

   If loop0 is already in use, you can also use loop1, loop2, etc.

3. Make filesystem for the device

   mkfs.ext3 /dev/loop0
   

4. Mount as a folder

   mount -t ext3 /dev/loop0 /mnt/disk1
   

   This way, the /mnt/disk1 folder can only use 1GB of space.

Unmount

1. First unmount the folder

   umount /mnt/disk1
   

2. Then unmount the device

   losetup -d /dev/loop0
   

3. Finally, delete the image file if not needed

   rm -f /root/disk.img