Why all recording and everything writing in /dev/mapper/VolGroup-lv_root

why all recording and everything writing in /dev/mapper/VolGroup-lv_root and /dev/mapper/VolGroup-lv_home not wiriting in this partition ??? space empty 1% only while other partition 50%

[[email protected] ~]# df -k
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/mapper/VolGroup-lv_root
51606140 21872656 27112044 45% /
tmpfs 1871232 0 1871232 0% /dev/shm
/dev/sda1 495844 34194 436050 8% /boot
/dev/mapper/VolGroup-lv_home
424786304 202992 403005380 1% /home

Because /var is part of the root volume group.

what is fix this coz root 50G small how to change size partation > without format

plz help