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Re: how to enable trim for an external encrypted SSD?

Am Mon, 06 Nov 2017 14:28:32 +0100 schrieb Christian Seiler:

> But all that doesn't really help you if the underlying LUKS container
> isn't opened with the discard option set. And as far as I know there is
> no possibility of tagging a LUKS container with that option, you must
> always supply that option to the cryptsetup command (which is done
> implicitly via /etc/crypttab).

Thanks for your detailed and extensive answer. That's exactly the answer 
I was afraid of. ;-)

So I will add an entry to the /etc/crypttab and hope that fstrim will do 
it's job. All system without a modified crypttab should mount the device 
but fstrim will fail. I think I can live with that solution.

> You could ask the LUKS developers to include an additional flag in their
> headers that allows you to specify that this volume should be opened
> with discards allowed by default

That is a good idea. I think I will write an ticket for that.

Thanks again.