/etc/sysctl.conf contains these lines:
dev.raid.speed_limit_min = 700000
dev.raid.speed_limit_max = 2000000

When rebooting, these error messages are logged to syslog:
localhost systemd-sysctl[538]: Couldn't write '700000' to
'dev/raid/speed_limit_min', ignoring: No such file or directory
localhost systemd-sysctl[538]: Couldn't write '2000000' to
'dev/raid/speed_limit_max', ignoring: No such file or directory

After the boot is complete, I entered these commands:
root@VMOSLeap152:/var/log > sysctl dev.raid.speed_limit_min
dev.raid.speed_limit_min = 1000
root@VMOSLeap152:/var/log > sysctl dev.raid.speed_limit_max
dev.raid.speed_limit_max = 200000
root@VMOSLeap152:/var/log > sysctl -p
dev.raid.speed_limit_min = 700000
dev.raid.speed_limit_max = 2000000
root@VMOSLeap152:/var/log > sysctl dev.raid.speed_limit_min
dev.raid.speed_limit_min = 700000
root@VMOSLeap152:/var/log > sysctl dev.raid.speed_limit_max
dev.raid.speed_limit_max = 2000000
root@VMOSLeap152:/var/log > 

This happens on both Leap 15.2 and Tumbleweed.
Temporary work around is to add "sysctl -p" to a shell script that runs
following reboot.