diff --git a/opennebula-images/freebsd-zfs-build-opennebula-image.sh b/opennebula-images/freebsd-zfs-build-opennebula-image.sh
index 41b845f..d3a2847 100755
--- a/opennebula-images/freebsd-zfs-build-opennebula-image.sh
+++ b/opennebula-images/freebsd-zfs-build-opennebula-image.sh
@@ -53,7 +53,9 @@ gpart add -t freebsd-zfs -l zfs0 -b 1M -s 5G md0
 zpool create -O compression=on -o ashift=12 -o altroot=/mnt -m none $ZPOOL md0p2
 
 zfs create -o mountpoint=none                                  $ZPOOL/ROOT
-zfs create -o mountpoint=/ -o canmount=noauto                  $ZPOOL/ROOT/default
+# We set zstd-19 so our image will become smaller, at the cost of a longer build time
+# At the end, we remove zstd-19 again, but all files already written will remain zstd-19 compressed
+zfs create -o mountpoint=/ -o canmount=noauto -o compression=zstd-19 $ZPOOL/ROOT/default
 mount -t zfs $ZPOOL/ROOT/default /mnt
 zpool set bootfs=$ZPOOL/ROOT/default $ZPOOL
 
@@ -133,6 +135,11 @@ env ASSUME_ALWAYS_YES=YES pkg -c /mnt install sudo bash curl base64 ruby open-vm
 env ASSUME_ALWAYS_YES=YES pkg -c /mnt clean --all
 rm /mnt/one-context.txz
 
+# Remove zstd-19 again, as it would be too slow for daily use.
+# But all files that were already writtne will remain zstd-19 compressed.
+# zstd-19 is slow to compress but fast to read.
+zfs inherit compression $ZPOOL/ROOT/default
+
 trap : EXIT
 cleanup