Rootfs on External Storage (extroot)
#df
Filesystem 1K-blocks Used Available Use% Mounted on
rootfs 15800240 85112 14905864 1% /
/dev/root 7168 7168 0 100% /rom
tmpfs 30568 312 30256 1% /tmp
tmpfs 512 0 512 0% /dev
/dev/sda1 15800240 85112 14905864 1% /
Use 1% of rootfs, after I use 83 Mb.