Re: [dm-crypt] 'discard' as default

On Thu, 2019-01-03 at 09:10 +0100, Milan Broz wrote:
> And maybe LUKS2 format (but not for LUKS1) should set TRIM flag by
> default,
> really would like to see opinions here.

As mentioned already by Arno... it's a question of mindset:

Anyone who's making reasonable use (i.e. really wants it and knows what
he wants) of dm-crypt/cryptsetup wants security as primary goal.

And this is also the main purpose of dm-crypt/cryptsetup.

So IMO, unless there are extremely strong reasons (like: system
otherwise completely unusable for everyone), one shouldn't lower the
standards per default (but rather give "good" documentation so that
users decide, still with the warning that not all implications might be
understood).

Today it might seem difficult for an attacker to draw much information
out of deletion patters.
But we've had the same in countless other security disasters, where one
was only afterwards smarter.



If someone wants the extra performance (anyway on SSDs only) and values
that higher than security, he can still enable it manually or just go
without encryption.
But why should those, who want to use dm-crypt/cryptsetup as intended
suffer (per default) for those who anyway rather misuse it?




Cheers,
Chris.