Hammam02,
You check size of harddisk by command #lspv hdiskx
eg.
PV IDENTIFIER: 00ccbfecffe46b80 VG IDENTIFIER 00ccbfec00004c000000000061578d91
PV STATE: active
STALE PARTITIONS: 0 ALLOCATABLE: yes
PP SIZE: 64 megabyte(s) LOGICAL VOLUMES: 3
TOTAL PPs: 255 (16320 megabytes) VG DESCRIPTORS: 1
FREE PPs: 177 (11328 megabytes) HOT SPARE: no
USED PPs: 78 (4992 megabytes) MAX REQUEST: 256 kilobytes
FREE DISTRIBUTION: 51..00..24..51..51
USED DISTRIBUTION: 00..51..27..00..00
and from command #lsvg | lsvg -i -l , you can figure out which LV is mounted on which disk.