Cleanly removing a PV from an LV or, how do I get more available extents?

I've been happily using LVM for a couple of months now to aggregate a bunch of disks together into one logical drive for a Debian box that I use as an over-the-network backup of my various other boxen. Thus far, it's been great.

Recently however, I started getting parity errors on one of the drives that's in my logical volume. It's a tiny drive that I threw in there merely because I had it, and its loss will not be missed. I just want to remove it altogether and pretend like it never existed. I'd like to preserve the data that's on the drive, if possible, but if not -- I'm ok
with losing it, since that data will come back next time I run my backups.

I read the FAQ, the HOWTO and scanned the mailing list archives and it appears that I need to do a pvmove to get the data off of that drive, and then a vgreduce to remove it from the volume group. Unfortunately, when I try to do the pvmove, I get:

% pvmove /dev/sdb
No extents available for allocation

I'm assuming that this means that there's nowhere to move the data that is on /dev/sdb. I further assume this means that I need some free physical extents somewhere. This is where I'm confused. When I set up LVM, I allocated all of my spare drives to it. So I have a 271GB logical volume of which I'm using only 32GB. So I know that I have free space to move the data around; I just don't know how to do it.

So. How do I get more free physical extents inside my logical volume? I feel confident that there's an easy answer for this that I overlooked, but I can't find it. Hopefully the context below will help a bit.

Thanks in advance,
-Bharat

================================

% lvdisplay
--- Logical volume ---

  LV Name                /dev/data/data1
  VG Name                data
  LV UUID                abrnMJ-2MqB-tkQl-g8g6-xYXx-KLE8-PMbNdG
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                275.19 GB
  Current LE             70448
  Segments               4
  Allocation             inherit
  Read ahead sectors     0
  Block device           254:0

% vgdisplay
--- Volume group ---
VG Name data
System ID

  Format                lvm2
  Metadata Areas        4
  Metadata Sequence No  8
  VG Access             read/write
  VG Status             resizable
  MAX LV                255
  Cur LV                1
  Open LV               1
  Max PV                255
  Cur PV                4
  Act PV                4
  VG Size               275.19 GB
  PE Size               4.00 MB
  Total PE              70448
  Alloc PE / Size       70448 / 275.19 GB
  Free  PE / Size       0 / 0
  VG UUID               PjytLd-X99E-iUTf-drKH-42dl-2QHO-6qBcmB

% pvdisplay
--- Physical volume ---

  PV Name               /dev/sda
  VG Name               data
  PV Size               34.20 GB / not usable 0
  Allocatable           yes (but full)
  PE Size (KByte)       4096
  Total PE              8755
  Free PE               0
  Allocated PE          8755
  PV UUID               q8ElTG-XOoB-nQy6-8VTU-wZlR-uj3b-Vrnxlp

--- Physical volume ---

  PV Name               /dev/sdb
  VG Name               data
  PV Size               8.55 GB / not usable 0
  Allocatable           yes (but full)
  PE Size (KByte)       4096
  Total PE              2189
  Free PE               0
  Allocated PE          2189
  PV UUID               dDZOFg-nQES-cCgO-l5KF-9JIz-i2hh-OpcP1V

--- Physical volume ---

  PV Name               /dev/sdc
  VG Name               data
  PV Size               34.25 GB / not usable 0
  Allocatable           yes (but full)
  PE Size (KByte)       4096
  Total PE              8768
  Free PE               0
  Allocated PE          8768
  PV UUID               B8dtE3-gdB7-aakQ-p4EY-CysX-b6VU-LrBYmc

--- Physical volume ---

  PV Name               /dev/hde7
  VG Name               data
  PV Size               198.19 GB / not usable 0
  Allocatable           yes (but full)
  PE Size (KByte)       4096
  Total PE              50736
  Free PE               0
  Allocated PE          50736
  PV UUID               bz31lu-ck6I-439l-IbWs-hb40-g6rm-rWE3oq

Your logical volume is 100% used by the filesystem. It sounds like the filesystem isn't full though, but LVM doesn't know that.

You need to shrink your filesystem, then shrink your LV, then use pvmove.

Dax Kelson
Guru Labs