diff --git a/tests/zfs-tests/tests/functional/cli_root/zfs_copies/zfs_copies.kshlib b/tests/zfs-tests/tests/functional/cli_root/zfs_copies/zfs_copies.kshlib
index 9911ccdf5..a7a93a304 100644
--- a/tests/zfs-tests/tests/functional/cli_root/zfs_copies/zfs_copies.kshlib
+++ b/tests/zfs-tests/tests/functional/cli_root/zfs_copies/zfs_copies.kshlib
@@ -153,5 +153,7 @@ function do_vol_test
 		log_must umount $mntp
 	fi
 
+	# Ubuntu 20.04 wants a sync here
+	log_must sync
 	log_must zfs destroy $vol
 }