I submitted this issue on SO before, but can’t get reasonable answers, so I re-post it here, thanks!
My host disk space usage is like this:
# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/rhel-root 50G 31G 20G 61% /
devtmpfs 5.8G 0 5.8G 0% /dev
tmpfs 5.8G 84K 5.8G 1% /dev/shm
tmpfs 5.8G 9.0M 5.8G 1% /run
tmpfs 5.8G 0 5.8G 0% /sys/fs/cgroup
/dev/mapper/rhel-home 1.3T 5.4G 1.3T 1% /home
/dev/sda2 497M 212M 285M 43% /boot
/dev/sda1 200M 9.5M 191M 5% /boot/efi
tmpfs 1.2G 16K 1.2G 1% /run/user/42
tmpfs 1.2G 0 1.2G 0% /run/user/0
After starting a docker container, the disk usage of this container is like follows:
# docker run -it mstormo/suse bash
606759b37afb:/ # df -h
Filesystem Size Used Avail Use% Mounted on
rootfs 99G 231M 94G 1% /
/dev/mapper/docker-253:0-137562709-606759b37afb809fe9224ac2210252ee1da71f9c0b315ff9ef570ad9c0adb16c 99G 231M 94G 1% /
tmpfs 5.8G 0 5.8G 0% /dev
shm 64M 0 64M 0% /dev/shm
tmpfs 5.8G 0 5.8G 0% /sys/fs/cgroup
tmpfs 5.8G 96K 5.8G 1% /run/secrets
/dev/mapper/rhel-root 50G 31G 20G 61% /etc/resolv.conf
/dev/mapper/rhel-root 50G 31G 20G 61% /etc/hostname
/dev/mapper/rhel-root 50G 31G 20G 61% /etc/hosts
tmpfs 5.8G 0 5.8G 0% /proc/kcore
tmpfs 5.8G 0 5.8G 0% /proc/timer_stats
I have 2 questions about container disk usage:
(1) The tmpfs and /dev/mapper/rhel-root in container share the same disk/memory space with host directly?
(2) For rootfs of container, where does this file system exist? As printed, it has 99G, so I can use all the 99G disk space?