Where Does Mailu Store Mail and Data?
Where Mailu keeps mail, settings, and queue data under its data root, and which subfolder holds what.
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Mailu stores all of its persistent state in one data root, /mailu by default, as a set of plain subfolders bind mounted into its containers. Mail bodies, the Postfix queue, DKIM keys, certificates, and the admin database each get their own folder. Nothing hides in anonymous volumes.
That single-root design makes the whole server portable: stop the stack, copy the root, start it elsewhere. Service overrides for nginx, Dovecot, and Postfix live in an overrides tree beside the data. Optional pieces like webmail and fetchmail add their own folders only when enabled.
Where Mailu stores this, by platform
/mailu
Default data root holding mail, mailqueue, data, dkim, certs, filter, and overrides subfolders. Back up the entire tree with the stack stopped. The compose files live here too, so the root documents its own deployment.
Frequently asked questions
how do I back up a Mailu server
Back up the whole data root, usually /mailu, with the stack stopped. Mail bodies live in mail, the queue in mailqueue, and admin settings in data. The database for the admin interface sits inside data too, so the tree restores as one unit.
where do I install Mailu from
Create the directory first, then move there before generating the compose files. The setup tool writes docker-compose.yml and mailu.env into the data root. Everything the stack persists lands in subfolders of that same root afterward.
where is queued mail vs delivered mail
Mail arrives in the mail folder per user, while the queue folder holds outbound and deferred mail. The filter folder carries antispam data and dkim holds signing keys. Certs and per-service overrides sit beside them under the same root.
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