Extend swap size (LVM)

swapon -s

swapoff /dev/vg_rhel6/lv_swap

lvextend -L +3GB /dev/vg_rhel6/lv_swap

mkswap /dev/vg_rhel6/lv_swap

swapon /dev/vg_rhel6/lv_swap

swapon -s

Ссылки:
http://www.techotopia.com/index.php/Adding_and_Managing_RHEL_6_Swap_Space