system:

Freshly kicked CentOS release 4.4 (Final)
Linux giant-backup-host 2.6.9-55.0.9.ELsmp #1 SMP Thu Sep 27 18:28:00 EDT 2007 x86_64 x86_64 x86_64 GNU/Linux

physical volumes:
two raid-5 on a 3ware 9000 controller; first is 7x298.09G, second is 8x298.09G

lvm:
  LVM version:     2.02.06 (2006-05-12)
  Library version: 1.02.07 (2006-05-11)
  Driver version:  4.5.5

pvdisplay output:

  --- Physical volume ---
  PV Name               /dev/sda3
  VG Name               two_raids
  PV Size               1.74 TB / not usable 0   
  Allocatable           yes 
  PE Size (KByte)       32768
  Total PE              57084
  Free PE               57084
  Allocated PE          0
  PV UUID               bGElGk-Wg1E-8CTV-Er1X-Ajdd-6q4f-hpjDi4
   
  --- Physical volume ---
  PV Name               /dev/sdb1
  VG Name               two_raids
  PV Size               2.04 TB / not usable 0   
  Allocatable           yes 
  PE Size (KByte)       32768
  Total PE              66754
  Free PE               66064
  Allocated PE          690
  PV UUID               tWRjzS-HBcD-8orQ-L7d0-jPXA-O1UM-h65qU3

vgdisplay output:

  --- Volume group ---
  VG Name               two_raids
  System ID             
  Format                lvm2
  Metadata Areas        2
  Metadata Sequence No  18
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                3
  Open LV               3
  Max PV                0
  Cur PV                2
  Act PV                2
  VG Size               3.78 TB
  PE Size               32.00 MB
  Total PE              123838
  Alloc PE / Size       690 / 21.56 GB
  Free  PE / Size       123148 / 3.76 TB
  VG UUID               UAGy8x-zDdQ-97QG-Utl8-1KuJ-WboB-iB9y6H

disk creation: 

# lvcreate -l 116900 -n data two_raids

error:

device-mapper: device 8:17 too small for target
device-mapper: dm-linear: Device lookup failed
device-mapper: error adding target to table
  device-mapper: reload ioctl failed: Invalid argument
  Failed to activate new LV.