Should this be default?
Which type of mirror?
What config options?

This request was evaluated by Red Hat Product Management for 
inclusion in the current release of Red Hat Enterprise Linux.
Since we are unable to provide this feature at this time,  
it has been proposed for the next release of 
Red Hat Enterprise Linux.

With lvm2 version 2.02.98 we support conversion from i.e. mirror LVs to thin pool. 

So user may select to use mirror for both - pool and metadata LV by this simple command:   

create mirrors  vg/lvmirror1 vg/lvmirror2

lvconvert --thinpool   vg/lvmirror1 --poolmetadata vg/lvmirror2

Lvm2 used to support conversion to mirrors - this has been however disabled by Jon's patch which generally disabled mirroring support for anything thin related.

The current state however seems to be not equally usable - since raid1 type seems to be pretty unconceivable to  create a raid1 on a single PV even when '--alloc anywhere' is in use.

So what does currently work is:

to convert thin pool data into mirrored:

lvconvert -m+1 --type raid1 vg/pool_tdata    


to convert thin pool metadata into mirrored metadata:

lvconvert -m+1 --type raid1 vg/pool_tmeta

Option for automated creation of mirror is not yet ready, user may already 'build' mirrored thin-pool metadata with 2 steps, eventually convert an existing thin-pool to a mirrored one.

Moving to 6.6 for separate option.