Dear Armbian community,
although I'm using Armbian a lot, I never had to submit anything to this forum (fortunately, because it works so well :-)),
On my PC I've experienced lags on heavy IO operations. After a short dig into available information,
I found a useful Cloudflare article on Kernel queues together with dm-crypt.
A good & short summary on possible actions for users can be found here:
https://wiki.archlinux.org/index.php/Dm-crypt/Specialties#Disable_workqueue_for_increased_solid_state_drive_(SSD)_performance
Enabling the no-read-workqueue & no-write-workqueue options helped a lot!
As I'm using a RockPi4 with the NVMe SSD with encryption, I thought this should apply to my SBC as well.
Unfortunately, Armbian/Debian Buster uses cryptsetup v2.1.0
which does NOT support these options.
According to the changelog, this option was introduced in v2.3.4:
https://gitlab.com/cryptsetup/cryptsetup/-/blob/master/docs/v2.3.4-ReleaseNotes
As Armbian uses a kernel > 5.9, the kernel infrastructure should be available.
Fortunately, crypsetup v2.3.4 exists in the buster-backports repo:
https://packages.debian.org/buster-backports/cryptsetup
Solution:
# sudo apt install cryptsetup/buster-backports
