I upgraded my postfix and dovecot mail server, turns out I forgot to configure delivery from postfix to dovecot. Postfix instead delivered the email itself(according to the logs as it's says "delivered"). The problem is I can't seem to find where Postfix stored the email for my users.
Can someone point me to the location(s) where postfix might have delivered it?
It depends on the address classes of your domain. That's why I ask postconf -n output and some maillog lines).
There are four address classes in postfix, two of them has capabilities to deliver it directly to mailbox: local domain class and virtual mailbox domain class.
If your domain listed on mydestination parameter, then it falls into local domain class. You should inspect parameter home_mailbox and mail_spool_directory to determine where the postfix save file. Below was snippet of man 8 local.
MAILBOX DELIVERY
The default per-user mailbox is a file in the UNIX mail spool directory (/var/mail/**user or **/var/spool/mail/**user); the location can be specified with the **mail_spool_directory configuration parameter. Specify a name ending in / for qmail-compatible maildir delivery.
Alternatively, the per-user mailbox can be a file in the user's home directory with a name specified via the home_mailbox configuration parameter. Specify a relative path name. Specify a name ending in / for qmail-compatible maildir delivery.
Otherwise if your domain listed on virtual_mailbox_domains parameter, then it falls into virtual mailbox domain class. You should inspect the value of virtual_mailbox_base and virtual_mailbox_maps value of specific recipient. virtual(8) delivery agent lookup the location of mailbox based on those parameters. Parameter $virtual_mailbox_base is unconditionally prepended to $virtual_mailbox_maps result, so the absolute path of email storage is $virtual_mailbox_base$virtual_mailbox_maps. See also man 8 virtual.
postconf -noutput and maillog lines when postfix get email