When copying the mailcow volumes you will see errors in docker, you will need to explicitly tell docker that these volumes have been copied

You will most likely see this in other scenarios, mailcow needs this when you are using the create_cold_standby.sh script

docker-compose.override.yml

volumes:
  clamd-db-vol-1:
    name: mailcowdockerized_clamd-db-vol-1
    external: true
  crypt-vol-1:
    name: mailcowdockerized_crypt-vol-1
    external: true
  mysql-socket-vol-1:
    name: mailcowdockerized_mysql-socket-vol-1
    external: true
  mysql-vol-1:
    name: mailcowdockerized_mysql-vol-1
    external: true
  postfix-vol-1:
    name: mailcowdockerized_postfix-vol-1
    external: true
  redis-vol-1:
    name: mailcowdockerized_redis-vol-1
    external: true
  rspamd-vol-1:
    name: mailcowdockerized_rspamd-vol-1
    external: true
  sogo-userdata-backup-vol-1:
    name: mailcowdockerized_sogo-userdata-backup-vol-1
    external: true
  sogo-web-vol-1:
    name: mailcowdockerized_sogo-web-vol-1
    external: true
  solr-vol-1:
    name: mailcowdockerized_solr-vol-1
    external: true
  vmail-index-vol-1:
    name: mailcowdockerized_vmail-index-vol-1
    external: true
  vmail-vol-1:
    name: mailcowdockerized_vmail-vol-1
    external: true