how to change disk space pointing directory at zimbra admin?

now pointing to /dev/mapper/rootvg-rootlv
(at zimbra admin when i click "disk" at domain server statistics, the graphical said Disk_Usage_/dev/mapper/rootvg-rootlv)
how to change it to point to /dev/mapper/rootvg-optlv ? or to dispay both at zimbra admin

server2:~ # df -h
Filesystem            Size  Used Avail Use% Mounted on
                       15G  7.2G  6.9G  52% /
udev                  1.5G  112K  1.5G   1% /dev
/dev/sda1              99M   12M   83M  13% /boot
                      141G   19G  115G  14% /opt
                      191G   39G  143G  22% /Backup
                      139G   14G  118G  11% /tmp/fakebackup