On every boot, my machine (CentOS 7) mounts all these:
# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 30G 2.6G 28G 9% /
devtmpfs 287M 0 287M 0% /dev
tmpfs 294M 0 294M 0% /dev/shm
tmpfs 294M 34M 261M 12% /run
tmpfs 294M 0 294M 0% /sys/fs/cgroup
But my /etc/fstab only contains these:
# cat /etc/fstab
UUID=823db525-82d9-467e-acdf-7379cbd85171 / xfs defaults 0 0
Where would all the mounts of "tmpfs" be defined?
Where can I configure their sizes?
If I add more entries in my /etc/fstab, such as something like:
tmpfs /dev/shm tmpfs defaults,noatime 0 0
Would that cause a conflict with whatever setting is already mounting that on boot?