I made the following test, changing the Max Volumes and Label Format. And worked like a charm:
*list pools
+--------+---------+---------+---------+----------+-------------+
| poolid | name | numvols | maxvols | pooltype | labelformat |
+--------+---------+---------+---------+----------+-------------+
| 1 | Default | 1 | 0 | Backup | * |
| 2 | File | 2 | 100 | Backup | * |
| 3 | Scratch | 0 | 0 | Backup | * |
+--------+---------+---------+---------+----------+-------------+
*quit
root@serpro-1552713:/etc/bacula# vi bacula-dir.conf
root@serpro-1552713:/etc/bacula# bconsole
Conectando ao Diretor localhost:9101
1000 OK: serpro-1552713-dir Version: 5.2.5 (26 January 2012)
Digite um período para cancelar um comando.
*reload
*list pools
Automatically selected Catalog: MyCatalog
Using Catalog "MyCatalog"
+--------+---------+---------+---------+----------+-------------+
| poolid | name | numvols | maxvols | pooltype | labelformat |
+--------+---------+---------+---------+----------+-------------+
| 1 | Default | 1 | 0 | Backup | * |
| 2 | File | 2 | 200 | Backup | file |
| 3 | Scratch | 0 | 0 | Backup | * |
+--------+---------+---------+---------+----------+-------------+
Anyway its necessary to | update > volume parameters > all volumes from all pools | to update the already created volumes.