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Asked: 2017-04-20 02:57:09 +0800 CST

What is /dev/loopx? [duplicate]

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$ df -kh
Filesystem      Size  Used Avail Use% Mounted on
udev            7,8G     0  7,8G   0% /dev
tmpfs           1,6G   19M  1,6G   2% /run
/dev/sda2       622G  227G  364G  39% /
tmpfs           7,8G  1,1G  6,7G  14% /dev/shm
tmpfs           5,0M  4,0K  5,0M   1% /run/lock
tmpfs           7,8G     0  7,8G   0% /sys/fs/cgroup
/dev/loop1      143M  143M     0 100% /snap/inkscape/2527
/dev/loop3       79M   79M     0 100% /snap/core/1441
/dev/loop0       79M   79M     0 100% /snap/core/1577
/dev/loop4       79M   79M     0 100% /snap/core/1512
/dev/loop2       62M   62M     0 100% /snap/pencilsheep/5
tmpfs           1,6G   92K  1,6G   1% /run/user/1000

What are these /dev/loop device files? My RAM is always full. Is this related?

loop-device

2 Answers

  1. Best Answer

    /dev/loop* are loop devices making plain files accessible as block devices. They have nothing to do with RAM occupation. They are typically used for mounting disk images, in your case apparently for Ubuntu Snap. See this Wikipedia article for details.

    Also note that it is a Good Thing(TM) your RAM is full. Unused RAM is wasted RAM, so Linux makes an effort to put all of your RAM to good use. See this info page for details.

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  2. That is normal. /dev/loopX are virtual devices to mount image files, these are -read only- so do not get larger or smaller than they are when created.

    Those mount points are connected to the snapd service. You will see extra loop devices added for every software you install using "snap". It can be removed by uninstalling the app via snapd.

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