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Lab 11.1 - my /dev/shm is not tmpfs [SOLVED - it`s normal]

dbuday Posts: 17

In Lab pdf stays:

$ df -h /dev/shm







Used Avail Use% Mounted on

24M 3.9G

1% /dev/shm

My output is:

df -h /dev/shm

Filesystem Size Used Avail Use% Mounted on

none 724M 212K 723M 1% /run/shm

My output shows Filesystem: none and Monted on /run/shm

Is it normal?


  • dbuday
    dbuday Posts: 17

    df -h | grep tmpfs
    tmpfs 145M 1,2M 144M 1% /run

    My only tmpfs is /run
  • coop
    coop Posts: 915
    This is normal. Exactly what is on tmpfs filesystems depends on your distribution; you did not mention what that is. For example on my (RHEL 7) system:

    $ df -h | grep tmpfs
    devtmpfs devtmpfs 7.8G 0 7.8G 0% /dev
    tmpfs tmpfs 7.8G 152M 7.7G 2% /dev/shm
    tmpfs tmpfs 7.8G 9.1M 7.8G 1% /run
    tmpfs tmpfs 7.8G 0 7.8G 0% /sys/fs/cgroup
    tmpfs tmpfs 1.6G 40K 1.6G 1% /run/user/1000

    You can have multiple tmpfs ramdisks mounted in fact as shown above.

    I've yet to see a distribution that doesn't use /dev/shm, but it's not essential to have it. Also note they are really not 7.8 GB in size here (which is half of my RAM). they are allowed to grow to that big but the size is dynamical.
  • dbuday
    dbuday Posts: 17
    Thank you mister Cooperstein for clearing this up for me; where will we be without your help.

    P.S. Distribution is Ubuntu 14.04


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