tmpfs are not really used as filesystems, but just take advantage of the filesystem abstraction. Applications can do I/O on a tmpfs. tmpfs functions reside purely in memory.
Creating a tmpfs special filesystem
1. Mount a new instance of tmpfs:
# mkdir /mnt/tmpfs # mount -t tmpfs none /mnt/tmpfs
Note: Check how much space the filesystem has been given and how much it is using.
# df -h /mnt/tmpfs Filesystem Size Used Avail Use% Mounted on none 915M 0 915M 0% /mnt/tmpfs
2. Once the filesystem is not more needed, unmount the filesystem
# umount /mnt/tmpfs
Virtually, modern Linux distributions mount an instance of tmpfs at /dev/shm.
# df -h /dev/shm Filesystem Size Used Avail Use% Mounted on tmpfs 915M 0 915M 0% /dev/shm
To check which instaces of tmpfs is using the system by default:
# df -h | grep tmpfs devtmpfs 901M 0 901M 0% /dev tmpfs 915M 0 915M 0% /dev/shm tmpfs 915M 9.6M 906M 2% /run tmpfs 915M 0 915M 0% /sys/fs/cgroup tmpfs 183M 28K 183M 1% /run/user/42 tmpfs 183M 3.5M 180M 2% /run/user/1000 tmpfs 183M 4.0K 183M 1% /run/user/0