root@server01:~# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda1             9.2G  6.1G  2.7G  70% /
/dev/sdb1             367G  345G  4.0G  99% /mnt/400GB
root@server01:~# tune2fs -m 2 /dev/sdb1
tune2fs 1.39 (29-May-2006)
Setting reserved blocks percentage to 2% (1953544 blocks)
root@server01:~# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda1             9.2G  6.1G  2.7G  70% /
/dev/sdb1             367G  345G   16G  96% /mnt/400GB
root@server01:~#