[linux-lvm] Cannot create a logical volume

[Vikas]

Objective: Be able to take snapshots of XEN disk images for backup.

Problem: lvcreate is failing

The environment:

[root at localhost ~]# pvscan
  PV /dev/md3   VG gt_vg   lvm2 [909.91 GB / 909.91 GB free]
  Total: 1 [909.91 GB] / in use: 1 [909.91 GB] / in no VG: 0 [0   ]

[root at localhost ~]# vgscan
  Reading all physical volumes.  This may take a while...
  Found volume group "gt_vg" using metadata type lvm2

[root at localhost ~]# vgdisplay gt_vg
  --- Volume group ---
  VG Name               gt_vg
  System ID
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  7
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                0
  Open LV               0
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               909.91 GB
  PE Size               32.00 MB
  Total PE              29117
  Alloc PE / Size       0 / 0
  Free  PE / Size       29117 / 909.91 GB
  VG UUID               j4aEP0-PCwG-Qyub-DCxw-aVVp-VyCK-EkZUsN

[root at localhost ~]# lvcreate -L 5G -n data gt_vg
  Not enough PVs with free space available for parallel allocation.
  Consider --alloc anywhere if desperate.

Any feedback would be very much appreciated,

Thanks for your time,

-- 
Vikas