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

Kumar amit mehta gmate.amit at gmail.com
Tue Jul 23 00:52:37 UTC 2013

On Mon, Jul 22, 2013 at 10:18:48PM +0200, Zdenek Kabelac wrote:
> It's your backend device used for thinpool data  which doesn't
> support discard. So it fallbacks to  nopassdown behaviour (discard
> is processed only at pool level).

So, it seems that my backend device(of which I've no idea!!) does not 
support discard.
> >I'm invoking these commands on a VM. I do not know, from where these
> >storage were mapped to my VM(were done my some storage admin). However
> Important piece of puzzle - if you want to see TRIM command hits your storage,
> your storage needs to support it ;)
> BTW it's perfectly ok to use thin pool only with nopassdown.
> Zdenek
> NOTE: issue_discard in lvm.conf is not related in any way with
> --discards option for thin pool creation.


Thank you for your time and answering my queries.


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