I'm confused between the various ways that
cryptsetup discard /TRIM operations can be enabled via the Linux kernel command line.
Allow using of discards (TRIM) requests on all LUKS partitions.
... If only a list of options, without an UUID, is specified, they apply to any UUIDs not specified elsewhere, and without an entry in /etc/crypttab. ...
rd.luks.options=discardis recommended here.
The Arch wiki section on LUKS and SSDs shows a third colon-seprated field:
- What is the difference between
allow-discards? Is the former mandatory and the second optional?
cryptdevice=/dev/sda2(eg not a UUID)? What if
cryptdevice=is given a UUID, does that count as "specified elsewhere"?
rd.luks.options=overwrite / append / prepend if
cryptsetup=already gives options?
- Is there any disadvantage to using
rd.luks.allow-discardswhich seems to be simplest if TRIM is wanted everywhere?