I am not sure if you wanted me to just add another -o, so I did these 3, but all with same results[1].
[1] [@ storage]# doveadm -D -o namespace/4archives/location=mdbox_deleted:/home/mail-archive/testtest/mdbox -o mail_location=mdbox_deleted:/home/mail-archive/testtest/mdbox:INDEX=/home/archiveindex/testtest/index mailbox status -u testtest 'messages vsize' "Archive/2018" Debug: Loading modules from directory: /usr/lib64/dovecot Debug: Module loaded: /usr/lib64/dovecot/lib15_notify_plugin.so Debug: Module loaded: /usr/lib64/dovecot/lib20_mail_log_plugin.so Debug: Module loaded: /usr/lib64/dovecot/lib20_replication_plugin.so Debug: Module loaded: /usr/lib64/dovecot/lib90_stats_plugin.so Debug: Loading modules from directory: /usr/lib64/dovecot/doveadm Debug: Skipping module doveadm_acl_plugin, because dlopen() failed: /usr/lib64/dovecot/doveadm/lib10_doveadm_acl_plugin.so: undefined symbol: acl_user_module (this is usually intentional, so just ignore this message) Debug: Skipping module doveadm_expire_plugin, because dlopen() failed: /usr/lib64/dovecot/doveadm/lib10_doveadm_expire_plugin.so: undefined symbol: expire_set_deinit (this is usually intentional, so just ignore this message) Debug: Skipping module doveadm_quota_plugin, because dlopen() failed: /usr/lib64/dovecot/doveadm/lib10_doveadm_quota_plugin.so: undefined symbol: quota_user_module (this is usually intentional, so just ignore this message) Debug: Module loaded: /usr/lib64/dovecot/doveadm/lib10_doveadm_sieve_plugin.so Debug: Skipping module doveadm_fts_lucene_plugin, because dlopen() failed: /usr/lib64/dovecot/doveadm/lib20_doveadm_fts_lucene_plugin.so: undefined symbol: lucene_index_iter_deinit (this is usually intentional, so just ignore this message) Debug: Skipping module doveadm_fts_plugin, because dlopen() failed: /usr/lib64/dovecot/doveadm/lib20_doveadm_fts_plugin.so: undefined symbol: fts_user_get_language_list (this is usually intentional, so just ignore this message) Debug: Skipping module doveadm_mail_crypt_plugin, because dlopen() failed: /usr/lib64/dovecot/doveadm/libdoveadm_mail_crypt_plugin.so: undefined symbol: mail_crypt_box_get_pvt_digests (this is usually intentional, so just ignore this message) doveadm(testtest): Debug: Effective uid=8267, gid=231, home=/home/popusers/testtest doveadm(testtest): Debug: replication: No mail_replica setting - replication disabled doveadm(testtest): Debug: Namespace inbox: type=private, prefix=, sep=/, inbox=yes, hidden=no, list=yes, subscriptions=yes location=mdbox_deleted:/home/mail-archive/testtest/mdbox:INDEX=/home/archiveindex/testtest/index doveadm(testtest): Debug: fs: root=/home/mail-archive/testtest/mdbox, index=/home/archiveindex/testtest/index, indexpvt=, control=, inbox=, alt= doveadm(testtest): Debug: Namespace 4archives: type=private, prefix=Archive/, sep=/, inbox=no, hidden=no, list=yes, subscriptions=yes location=mdbox_deleted:/home/mail-archive/testtest/mdbox doveadm(testtest): Debug: fs: root=/home/mail-archive/testtest/mdbox, index=, indexpvt=, control=, inbox=, alt= doveadm(testtest): Debug: Archive/2018: Mailbox opened because: mailbox status doveadm(testtest): Error: Mailbox Archive/2018: Failed to lookup mailbox status: Mailbox doesn't exist: Archive/2018
[@ storage]# doveadm -D -o namespace/4archives/location=mdbox_deleted:/home/mail-archive/testtest/mdbox:INDEX=/home/archiveindex/testtest/index mailbox status -u testtest 'messages vsize' "Archive/2018" Debug: Loading modules from directory: /usr/lib64/dovecot Debug: Module loaded: /usr/lib64/dovecot/lib15_notify_plugin.so Debug: Module loaded: /usr/lib64/dovecot/lib20_mail_log_plugin.so Debug: Module loaded: /usr/lib64/dovecot/lib20_replication_plugin.so Debug: Module loaded: /usr/lib64/dovecot/lib90_stats_plugin.so Debug: Loading modules from directory: /usr/lib64/dovecot/doveadm Debug: Skipping module doveadm_acl_plugin, because dlopen() failed: /usr/lib64/dovecot/doveadm/lib10_doveadm_acl_plugin.so: undefined symbol: acl_user_module (this is usually intentional, so just ignore this message) Debug: Skipping module doveadm_expire_plugin, because dlopen() failed: /usr/lib64/dovecot/doveadm/lib10_doveadm_expire_plugin.so: undefined symbol: expire_set_deinit (this is usually intentional, so just ignore this message) Debug: Skipping module doveadm_quota_plugin, because dlopen() failed: /usr/lib64/dovecot/doveadm/lib10_doveadm_quota_plugin.so: undefined symbol: quota_user_module (this is usually intentional, so just ignore this message) Debug: Module loaded: /usr/lib64/dovecot/doveadm/lib10_doveadm_sieve_plugin.so Debug: Skipping module doveadm_fts_lucene_plugin, because dlopen() failed: /usr/lib64/dovecot/doveadm/lib20_doveadm_fts_lucene_plugin.so: undefined symbol: lucene_index_iter_deinit (this is usually intentional, so just ignore this message) Debug: Skipping module doveadm_fts_plugin, because dlopen() failed: /usr/lib64/dovecot/doveadm/lib20_doveadm_fts_plugin.so: undefined symbol: fts_user_get_language_list (this is usually intentional, so just ignore this message) Debug: Skipping module doveadm_mail_crypt_plugin, because dlopen() failed: /usr/lib64/dovecot/doveadm/libdoveadm_mail_crypt_plugin.so: undefined symbol: mail_crypt_box_get_pvt_digests (this is usually intentional, so just ignore this message) doveadm(testtest): Debug: Effective uid=8267, gid=231, home=/home/popusers/testtest doveadm(testtest): Debug: replication: No mail_replica setting - replication disabled doveadm(testtest): Debug: Namespace inbox: type=private, prefix=, sep=/, inbox=yes, hidden=no, list=yes, subscriptions=yes location=mdbox:~/mdbox:INDEX=/home/popindex/testtest/index:CONTROL=~/mail/control doveadm(testtest): Debug: fs: root=/home/popusers/testtest/mdbox, index=/home/popindex/testtest/index, indexpvt=, control=/home/popusers/testtest/mail/control, inbox=, alt= doveadm(testtest): Debug: Namespace 4archives: type=private, prefix=Archive/, sep=/, inbox=no, hidden=no, list=yes, subscriptions=yes location=mdbox_deleted:/home/mail-archive/testtest/mdbox:INDEX=/home/archiveindex/testtest/index doveadm(testtest): Debug: fs: root=/home/mail-archive/testtest/mdbox, index=/home/archiveindex/testtest/index, indexpvt=, control=, inbox=, alt= doveadm(testtest): Debug: Archive/2018: Mailbox opened because: mailbox status doveadm(testtest): Error: Mailbox Archive/2018: Failed to lookup mailbox status: Mailbox doesn't exist: Archive/2018
[@ storage]# doveadm -D -o namespace/4archives/location=mdbox_deleted:/home/mail-archive/testtest/mdbox mailbox status -u testtest 'messages vsize' "Archive/2018" Debug: Loading modules from directory: /usr/lib64/dovecot Debug: Module loaded: /usr/lib64/dovecot/lib15_notify_plugin.so Debug: Module loaded: /usr/lib64/dovecot/lib20_mail_log_plugin.so Debug: Module loaded: /usr/lib64/dovecot/lib20_replication_plugin.so Debug: Module loaded: /usr/lib64/dovecot/lib90_stats_plugin.so Debug: Loading modules from directory: /usr/lib64/dovecot/doveadm Debug: Skipping module doveadm_acl_plugin, because dlopen() failed: /usr/lib64/dovecot/doveadm/lib10_doveadm_acl_plugin.so: undefined symbol: acl_user_module (this is usually intentional, so just ignore this message) Debug: Skipping module doveadm_expire_plugin, because dlopen() failed: /usr/lib64/dovecot/doveadm/lib10_doveadm_expire_plugin.so: undefined symbol: expire_set_deinit (this is usually intentional, so just ignore this message) Debug: Skipping module doveadm_quota_plugin, because dlopen() failed: /usr/lib64/dovecot/doveadm/lib10_doveadm_quota_plugin.so: undefined symbol: quota_user_module (this is usually intentional, so just ignore this message) Debug: Module loaded: /usr/lib64/dovecot/doveadm/lib10_doveadm_sieve_plugin.so Debug: Skipping module doveadm_fts_lucene_plugin, because dlopen() failed: /usr/lib64/dovecot/doveadm/lib20_doveadm_fts_lucene_plugin.so: undefined symbol: lucene_index_iter_deinit (this is usually intentional, so just ignore this message) Debug: Skipping module doveadm_fts_plugin, because dlopen() failed: /usr/lib64/dovecot/doveadm/lib20_doveadm_fts_plugin.so: undefined symbol: fts_user_get_language_list (this is usually intentional, so just ignore this message) Debug: Skipping module doveadm_mail_crypt_plugin, because dlopen() failed: /usr/lib64/dovecot/doveadm/libdoveadm_mail_crypt_plugin.so: undefined symbol: mail_crypt_box_get_pvt_digests (this is usually intentional, so just ignore this message) doveadm(testtest): Debug: Effective uid=8267, gid=231, home=/home/popusers/testtest doveadm(testtest): Debug: replication: No mail_replica setting - replication disabled doveadm(testtest): Debug: Namespace inbox: type=private, prefix=, sep=/, inbox=yes, hidden=no, list=yes, subscriptions=yes location=mdbox:~/mdbox:INDEX=/home/popindex/testtest/index:CONTROL=~/mail/control doveadm(testtest): Debug: fs: root=/home/popusers/testtest/mdbox, index=/home/popindex/testtest/index, indexpvt=, control=/home/popusers/testtest/mail/control, inbox=, alt= doveadm(testtest): Debug: Namespace 4archives: type=private, prefix=Archive/, sep=/, inbox=no, hidden=no, list=yes, subscriptions=yes location=mdbox_deleted:/home/mail-archive/testtest/mdbox doveadm(testtest): Debug: fs: root=/home/mail-archive/testtest/mdbox, index=, indexpvt=, control=, inbox=, alt= doveadm(testtest): Debug: Archive/2018: Mailbox opened because: mailbox status doveadm(testtest): Error: Mailbox Archive/2018: Failed to lookup mailbox status: Mailbox doesn't exist: Archive/2018