[dm-devel] [PATCH 0/3] dm raid/raid1: enable discard support when any devices support discard

[Ondrej Kozina]

On 4/20/20 12:13 PM, Paul Wise wrote:
> On Mon, 2020-04-20 at 09:35 +0200, Ondrej Kozina wrote:
> 
>> Did you have discard allowed on both dm-crypt devices? dm-crypt
>> (kernel) does not allow discards by default.
> 
> I did not, I guess that explains why I got no errors.
> 

FYI if you use LUKS2 metadata format for encrypted drives, you can 
enable discards by default once and for all by following command:

cryptsetup open /dev/sdx sdx_unlocked --allow-discards --persistent

Any following unlock will enable discards automatically.

Regards O.