Re: Any way in LVM to deal with 512e vs 4Kn physical devices?

[Zdenek Kabelac <zdenek.kabelac@gmail.com>]

Dne 17. 01. 24 v 12:21 Andy Smith napsal(a):
> Hi Zdenek,
> 
> On Wed, Jan 17, 2024 at 11:36:24AM +0100, Zdenek Kabelac wrote:
>> Lvm tool as such doesn't really have any problems with mixing 4K and 512b
>> disks within a single VG
> 
> That's interesting, though in my case I have done a block-based
> copy of an LV from a system where all PVs are 512b to one where all
> PVs are 4K.
> 
> So out of interest, what does LVM do when one PV within same VG says
> 512b and another says 4K - just pass on 512b for every LV I assume,
> unless allow_mixed_block_size is set as you mention?

lvm2 does nothing with disks.
How they are configured, that way they work.

There is nothing that would try to make 4K disks to be like 512b.

Although I believe there were some DM targets for such emulation built, but 
they are not upstream.

So if user had an old VG with mixed blocks created before protection was added 
to lvm2 -- they will continue to work with all the 'risks' - and lvm2 will 
show up some warnings here and there.

With new disks users are not allowed (by default) to mix them together with 
one VG.

Regards

Zdenek