Best EXPORT_TYPES configuration to backup mail, calendars, and contacts

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1

Your question

Hi all,
I am trying to set up a selective backup strategy for a testing machine. My goal is to export only user-specific data (all emails, attachments, calendars, and contacts), while completely excluding the server configuration, domains, global settings.

What is the absolute best combination for EXPORT_TYPES to achieve a clean backup of emails, calendars, and contacts while completely stripping out server settings? Is “data,blob,changelog” the correct way to go?

Thank you for your help!

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2

Here is a precise breakdown to answer your question directly.

What each EXPORT_TYPES family actually contains

Looking at the source, each family maps to specific database subspaces:

Family Subspaces included
data ACLs, indexes, quotas, counters, properties (email metadata, mailbox structure, calendar/contact metadata)
blob Blob content + blob links (actual email bodies, attachments, calendar/contact file content)
registry The internal object registry + the internal directory (accounts, principals)
changelog IMAP CONDSTORE/incremental sync logs
queue Outbound mail queue messages and events
report Outgoing/incoming DMARC/TLS reports
telemetry Tracing spans and metrics
tasks Background task queue

Recommendation for your goal

To capture all user data (emails, attachments, calendars, contacts) while excluding server/global configuration, the correct combination is:

EXPORT_TYPES="data,blob,registry"

Here is why:

  • data holds all structured user data: email metadata, mailbox layout, calendar metadata, contact metadata, ACLs, quotas.
  • blob holds the actual binary content: email bodies, attachments, calendar .ics files, vCards, etc.
  • registry holds the account/principal definitions that own the above data. Without it, the exported data has no user accounts to attach to.

changelog is optional for a backup. It is only needed if you want IMAP CONDSTORE (flag-change history) to survive the restore intact. It does not contain any message or contact content, so you can safely omit it for a clean user-data-only backup.

queue, report, telemetry, tasks are all operational/transient data – in-flight messages, aggregate reports, metrics – and are not part of user mailbox/calendar/contact data.

Important caveat from the docs: The export/import tool is explicitly described as “not a substitute for proper backup procedures” and is designed for database migration. For routine backups, the docs recommend using your database backend’s native tools (e.g., pg_dump for PostgreSQL, filesystem snapshots for RocksDB).

Relevant docs: Database Migration - Choosing what to export and Database Internals.

This is an automated reply from the Stalwart Help Bot. Other community members may follow up if this answer is incomplete or wrong.

3

Snapshot for server configuration, Vandelay for account backups. The exact split you are looking for.

4

@Disrupt Yes, but backups are per account only.