On a CentOS 7 machine, I've had several instances recently where filesystems mounted manually (not using an entry in fstab) suddenly get unmounted.
This always occurs when I/O is occurring on the volumes. I've seen it happen for both physical disks and ramdisks.
In all cases, the filesystems had been mounted for at least 24 hours.
Is there a difference in the way mounts are handled by Linux systems, depending on whether they're mounted manually or from fstab?
The mount commands I used were:
sudo mount -t tmpfs -o 10G none /ramdisk sudo mount -t xfs /dev/sda1 /Vol1