Problem extending a Logical Volume

[Dave In Sidney]

I am running Ubuntu 12.04.1 as a headless server and am having troubles extending the Logical Volume Group I use for /home.
I initially had a single 2TB drive and tried adding a 2nd 2TB drive, but it seems that the second drive is only partially recognized as indicated by df:

Filesystem 1K-blocks Used Available Use% Mounted on
/dev/sda1 60475476 6948644 50454836 13% /
udev 1793400 12 1793388 1% /dev
tmpfs 720856 1052 719804 1% /run
none 5120 0 5120 0% /run/lock
none 1802136 0 1802136 0% /run/shm
/dev/mapper/vgServerData-HomeData 1902411892 1879712776 22699116 99% /home

lvdisplay shows:
LV Name /dev/vgServerData/HomeData
VG Name vgServerData
LV UUID M38qXv-qTyh-4AGM-d3vv-n3Dh-bekt-tHrKVl
LV Write Access read/write
LV Status available
# open 1
LV Size 1.80 TiB
Current LE 471860
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 252:0

pvdsiplay shows:
PV Name /dev/sdb1
VG Name vgServerData
PV Size 1.82 TiB / not usable 4.00 MiB
Allocatable yes
PE Size 4.00 MiB
Total PE 476931
Free PE 5071
Allocated PE 471860
PV UUID Z49mnJ-mhP6-kEmt-98QC-ZXLF-ZkVl-zLO1CN

--- Physical volume ---
PV Name /dev/sdc1
VG Name vgServerData
PV Size 1.82 TiB / not usable 4.00 MiB
Allocatable yes
PE Size 4.00 MiB
Total PE 476931
Free PE 476931
Allocated PE 0
PV UUID p5iU3b-Bheh-1Nbo-1mFK-SJhG-3vHU-2lfeAt

and vgdisplay shows:
VG Name vgServerData
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 14
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 1
Max PV 0
Cur PV 2
Act PV 2
VG Size 3.64 TiB
PE Size 4.00 MiB
Total PE 953862
Alloc PE / Size 471860 / 1.80 TiB
Free PE / Size 482002 / 1.84 TiB
VG UUID 0pFaE1-VzH2-NlmA-TnEN-EU3q-SOa2-7Ra29H


Any and all help and suggestions gratefully appreciated!!

[Dave In Sidney]

A little more research and I discovered that I needed to do:
- lvextend
- resize2fs