# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 50G 1.9G 45G 5% /
tmpfs 1.9G 0 1.9G 0% /dev/shm
/dev/sda3 77G 469M 73G 1% /opt
/etc/fstab
......
tmpfs /dev/shm tmpfs defaults,size=1g 0 0
......
mount -o remount /dev/shm
# mount -o remount,rw /dev/shm