Excessive disk activity

I have installed OpenSuse Tumbleweed on a Lenovo W510 laptop. Periodically, I see the disk-activity light come on after booting the system and it remains on for quite a long time. I ran ‘top’ and a process running ‘fstrim’ appears near the top quite frequently. This machine has a mechanical disk. Why is fstrim running (my understanding is that this is for SSDs)? How can I disable it? I’m guessing that it is the cause of this disk activity. System performance while this is going on is naturally very poor.

OpenSuse is the only system installed on this machine and the file-system setup is exactly as the installer proposed: btrfs for the system and xfs for /home.

Any help appreciated –
/Don Allen

Show /etc/fstab

UUID=16b29160-7c2d-441f-b474-b83d345d103d swap swap defaults 0 0
UUID=a1fa1b66-ef1a-447c-a626-dac02adb5805 / btrfs defaults 0 0
UUID=a1fa1b66-ef1a-447c-a626-dac02adb5805 /boot/grub2/i386-pc btrfs subvol=@/boot/grub2/i386-pc 0 0
UUID=a1fa1b66-ef1a-447c-a626-dac02adb5805 /boot/grub2/x86_64-efi btrfs subvol=@/boot/grub2/x86_64-efi 0 0
UUID=a1fa1b66-ef1a-447c-a626-dac02adb5805 /opt btrfs subvol=@/opt 0 0
UUID=a1fa1b66-ef1a-447c-a626-dac02adb5805 /srv btrfs subvol=@/srv 0 0
UUID=a1fa1b66-ef1a-447c-a626-dac02adb5805 /tmp btrfs subvol=@/tmp 0 0
UUID=a1fa1b66-ef1a-447c-a626-dac02adb5805 /usr/local btrfs subvol=@/usr/local 0 0
UUID=a1fa1b66-ef1a-447c-a626-dac02adb5805 /var/cache btrfs subvol=@/var/cache 0 0
UUID=a1fa1b66-ef1a-447c-a626-dac02adb5805 /var/crash btrfs subvol=@/var/crash 0 0
UUID=a1fa1b66-ef1a-447c-a626-dac02adb5805 /var/lib/libvirt/images btrfs subvol=@/var/lib/libvirt/images 0 0
UUID=a1fa1b66-ef1a-447c-a626-dac02adb5805 /var/lib/mailman btrfs subvol=@/var/lib/mailman 0 0
UUID=a1fa1b66-ef1a-447c-a626-dac02adb5805 /var/lib/mariadb btrfs subvol=@/var/lib/mariadb 0 0
UUID=a1fa1b66-ef1a-447c-a626-dac02adb5805 /var/lib/mysql btrfs subvol=@/var/lib/mysql 0 0
UUID=a1fa1b66-ef1a-447c-a626-dac02adb5805 /var/lib/named btrfs subvol=@/var/lib/named 0 0
UUID=a1fa1b66-ef1a-447c-a626-dac02adb5805 /var/lib/pgsql btrfs subvol=@/var/lib/pgsql 0 0
UUID=a1fa1b66-ef1a-447c-a626-dac02adb5805 /var/log btrfs subvol=@/var/log 0 0
UUID=a1fa1b66-ef1a-447c-a626-dac02adb5805 /var/opt btrfs subvol=@/var/opt 0 0
UUID=a1fa1b66-ef1a-447c-a626-dac02adb5805 /var/spool btrfs subvol=@/var/spool 0 0
UUID=a1fa1b66-ef1a-447c-a626-dac02adb5805 /var/tmp btrfs subvol=@/var/tmp 0 0
UUID=a1fa1b66-ef1a-447c-a626-dac02adb5805 /.snapshots btrfs subvol=@/.snapshots 0 0
UUID=fa2c949a-05ba-4192-826d-8ea4dd92bb91 /home xfs defaults 1 2

That looks ok maybe it is snapper it may require ftrim. That also rebalances the btree so may be lengthy. ftrim releases deleted blocks so does have use in non SSD drives also.