[linux-lvm] lvcreate --thin gives "unknown segment type" error

Kumar amit mehta gmate.amit at gmail.com
Mon Jul 22 10:57:42 UTC 2013

On Mon, Jul 22, 2013 at 02:15:36PM +0200, Zdenek Kabelac wrote:
> configure --with-thin=internal
> (and you will likely miss  '--enable-udev_sync'
Thank you, it worked!

However, It seems that "discards" behavior for thin pool is not
supported on RHEL 6.4. Please confirm. 
# ./configure --with-thin=internal --enable-debug

# make; make install

# lvcreate --discards passdown -L 1G -T thinvg1/thinlv1
  Logical volume "thinlv1" created

# lvs -o +devices|grep -i thinlv1
  thinlv1       thinvg1       twi-a-tz-   1.00g               0.00

# dmesg
device-mapper: thin: Data device (dm-3) discard unsupported: Disabling
discard passdown.

        if (reason) {
                DMWARN("Data device (%s) %s: Disabling discard
passdown.", bdevname(data_bdev, buf), reason);
                pt->adjusted_pf.discard_passdown = false;

Seems that we'll reach here if QUEUE_FLAG_DISCARD flag in the request
queue is not set.


More information about the linux-lvm mailing list