Can't change passwd

Hi guys I need your help !

I found document relate to "recovery password"

but that is not work well (https://support.f5.com/csp/article/K35811337)

I tried to mount new volume but, some problem occurred

switch_root:/# mount | grep /dev/mapper/vg--db

/dev/mapper/vg--db--sde-set.3.root on /sysroot type ext3 (ro,relatime,errors=continue,barrier=0,data=ordered)

/dev/mapper/vg--db--sde-set.3._usr on /sysroot/usr type ext3 (ro,noatime,errors=continue,barrier=0,data=ordered)

switch_root:/# mount -o remount,rw /sysroot

switch_root:/# mount -o remount,rw /sysroot/usr

switch_root:/# mount /dev/mapper/vg--db--sda-set.2._config /sysroot/config

mount: special device /dev/mapper/vg--db--sda-set.2._config does not exist

switch_root:/# mount /dev/mapper/vg--db--sda-set.1._config /sysroot/config 

mount: special device /dev/mapper/vg--db--sda-set.1._config does not exist

switch_root:/# mount /dev/mapper/vg--db--sda-set.3._config /sysroot/config 

mount: special device /dev/mapper/vg--db--sda-set.3._config does not exist

how to solve that ,, please let me know if you know that !

thank you