Attempting to extend logical volume

[Robert Griffin_1]

I can't extend a volume group. I seem to have plenty of physical extents (see vgdisplay and lvdisplay output below). These drives are mirrored and striped (level 0+1).

lvextend -L 12300 /dev/vgopt/lvopt10
lvextend: Not enough free physical extents available.
Logical volume "/dev/vgopt/lvopt10" could not be extended.

lvdisplay /dev/vgopt/lvopt10
--- Logical volumes ---
LV Name /dev/vgopt/lvopt10
VG Name /dev/vgopt
LV Permission read/write
LV Status available/syncd
Mirror copies 1
Consistency Recovery MWC
Schedule parallel
LV Size (Mbytes) 12192
Current LE 3048
Allocated PE 6096
Stripes 0
Stripe Size (Kbytes) 0
Bad block on
Allocation PVG-strict/distributed
IO Timeout (Seconds) default

vgdisplay vgopt
--- Volume groups ---
VG Name /dev/vgopt
VG Write Access read/write
VG Status available
Max LV 255
Cur LV 17
Open LV 18
Max PV 16
Cur PV 12
Act PV 12
Max PE per PV 4341
VGDA 24
PE Size (Mbytes) 4
Total PE 52080
Alloc PE 41124
Free PE 10956
Total PVG 0
Total Spare PVs 0
Total Spare PVs in use 0

[James R. Ferguson]

Hi Robert:

The problem is the you do not have sufficient unused, physical extents available on each physical volume of the volume group to "round-robin" allocate new logical extents.

In addition, you have a PVG-strict mirror policy, along with this distributed allocation policy. This means that mirrors of a logical
extent cannot share the same physical volume group.

Regards!

...JRF...

[Tim D Fulford]

If you are mirroring the LV, which I think you are, there may not be enough free extents on all the disks. e.g most of the free extents is on one disk & very little on the other. Do

# vgdisplay -v | egrep "PV Name|Free PE"

This will show how much free space is on each disk.

Tim

[Roger Baptiste]

Do a Vgdisplay -v and look at the
"Free PE" entries to see how many Free PE's
you have got available for each disk(physical
volume). Since you are using mirroring,
the number of PE's used for the primary
will be half of those displayed.

All this means that, the 'Free PE" of VG
(as shown in vgdisplay) is not necessarily
something which is available for use totally,
on a PVG-strict, mirrored environment.

IF you really want to extend this LV,
then you can do it by reducing it's mirror
(lvreduce -m 0 lvname ) and
then extend the LV. But, it may scatter
your VG layout.

HTH
raj