Arch Linux

neo-alchemist

Member

Registered: 2017-08-25

Posts: 2

Need help enabling TRIM over dm-crypt

Below is the line in /etc/default/grub the Arch Wiki tells me to edit to allow TRIM support for the encrypted root. I did not touch this afterwards. It's configured as the Wiki suggested.

GRUB_CMDLINE_LINUX_DEFAULT="quiet cryptdevice=UUID=<uuid_stuff>:cryptolvm root=/dev/mapper/archvol-root"

Question is: where do I put :allow-discards ?

Placing it after root=/(...)/ locked me out of the system and I had to chroot my way to fix. Placing it after ":cryptolvm" caused the same error. By the way, /etc/lvm/lvm.conf is already set. All I need now is to enable it to pass through encryption.

Slithery

Administrator

From: Norfolk, UK

Registered: 2013-12-01

Posts: 5,776

Re: Need help enabling TRIM over dm-crypt

To add support during boot, you will need to add :allow-discards to the cryptdevice option. The TRIM option may look like this:

cryptdevice=/dev/sdaX:root:allow-discards

So in your case the :allow-discards comes immedietely after cryptdevice=UUID=<uuid_stuff>:cryptolvm

Last edited by Slithery (2017-08-25 10:46:21)

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No, it didn't "fix" anything. It just shifted the brokeness one space to the right. - jasonwryan
Closing -- for deletion; Banning -- for muppetry. - jasonwryan

aur - dotfiles

neo-alchemist

Member

Registered: 2017-08-25

Posts: 2

Re: Need help enabling TRIM over dm-crypt

To add support during boot, you will need to add :allow-discards to the cryptdevice option. The TRIM option may look like this:

cryptdevice=/dev/sdaX:root:allow-discards

So in your case the :allow-discards comes immedietely after cryptdevice=UUID=<uuid_stuff>:cryptolvm

Thanks, that was it. I tried it before, but probably forgot to update grub afterwards.

Just one last thing, please.
Is it important to use TRIM on the EFI (FAT32) partition too? It's a 500MB partition. Fedora had it enabled by default but I couldn't find instructions and clarification.