On 2020-12-20 19:12, Martin Jørgensen wrote: > *"Note that if you're using LVM or cryptsetup, all such layers need to be > configured to pass through the discard operation to the lower layer. By > default, cryptsetup ignores discard operations as it prioritizes privacy > over performance – TRIM by its nature reveals which disk areas are in use > and which ones are free."* So, if I understand correctly, this means that even though the fstrim utility runs every once in a while and sends TRIM commands down the pipe, they will be caught and stopped by the dm-crypt layer unless it is also configured to let them pass. In this case the only thing I need to do is activate TRIM on dm-crypt since I don't use LVM. > For the last part I now think I understand the need for passing through > discard operations to the lower layer (haven't done it but also haven't had > problems in years using LUKS). I think something like this could be what > you're looking for: > https://blog.christophersmart.com/2013/06/05/trim-on-lvm-on-luks-on-ssd/ - > I found several similar posts on google, it seems you basically need to > ensure that discards are sent to the crypto layer by adding the > *allow-discards* option to /etc/crypttab... Haven't actually done it myself > - maybe I should do that in near future, sounds like a good idea... The /etc/crypttab should use the keyword "discard" according to debian documentation. I believe that "allow-discards" is meant to be a kernel parameter passed by the bootloader. I've also seen "rd.luks.allow-discards" or "rd.luks.options=discard" used on some pages. We'll see, if any work for me. To test, I'm going to use the following command: # dmsetup table | grep allow_discards Kind regards, M. _______________________________________________ dm-crypt mailing list dm-crypt@xxxxxxxx https://www.saout.de/mailman/listinfo/dm-crypt
