Since Unraid doesn't retain modifications between reboots, you have to disable the mover after each reboot.
To disable the Unraid's mover completely upon each boot, simply add:
sed -i '/^start()/a echo "Mover disabled!" && exit 0' "$(which mover)"
to the end of your /boot/config/go to disable Unraid's mover.
(This file gets executed upon booting)
At the end, your /boot/config/go should look like something like this:
#!/bin/bash
sed -i '/^start()/a echo "Mover disabled!" && exit 0' "$(which mover)"
If you use ZFS, then Unraid's mover can get in the way of ZFS replication because the mover uses rsync. And personally, I have my own ZFS backup solution that replicates and snapshots from the cache pool to array pool.
Unraid's forum suggest disabling the mover for a share by setting its 'Second Storage' to none! No one wants to go through all of their cache -> array (or cache <- array) ZFS shares to cache (or array) just to prevent the mover from moving those shares. Also from my experience, ZFS's replication is way faster than rsync (plus you can have snapshots as a bonus).