Currently the number of extents in any LV is limited to 32 bits. Large LVs use large extent sizes.
But with thin, mostly sparse, LVs, there comes a need for large LVs to have small extent sizes.
Consider compatibility, perhaps limiting this to thin LVs in the first instance.
*** Bug 815181 has been marked as a duplicate of this bug. ***
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.
We do map (small) thin chunks onto a thin pool DataLV with the current solution and keep track of their mapping on a thin MetaLV managed by the thin target, hence we don't require 64 bit extent numbers any more -> closing.
Feel free to reopen in case another requirement arises.
The reason why to support this is quite simple -
When you create 'small' extent size - you can't create large volume size - so the comment 8 is not really relevant.
With 4MB extent you cannot create 4EB thin volume - even though there is not other technical limitation - the total size of LV is still expressed as 32bit * 32bit number.
I don't see us getting to this self-imposed feature. I've also heard no requests for this from customers...