It is easy to assume an email archive counts as your backup, but they answer different questions. A backup answers "how do we get the whole server working again after the disk dies / the VM is corrupted / ransomware hits it." An archive answers "can we find and prove what a specific message said six months ago," and is usually not designed to bring a dead server back to life quickly.
You generally need both, for different reasons, and neither substitutes for the other. If retention and legal search are the actual requirement, see email retention policy and the archiving product pages — this guide is specifically about getting a working mail server back after something goes wrong.
A mail server has more moving parts than "the mailbox files." A backup plan that misses any of these leaves a gap:
- The mailbox/message store itself — the actual mail data, whatever format your server uses.
- Configuration — users, domains, routing rules, spam filter settings, connector configuration. Rebuilding this from memory after a failure is slow and error-prone.
- TLS certificates and private keys — losing these means new certificates and, briefly, security warnings or failed connections until replacements are issued and trusted.
- DNS records, documented somewhere other than the server — MX, SPF, DKIM, DMARC. If the server dies and DNS access is only remembered by the person who set it up years ago, recovery stalls on this, not on restoring mail data.
- Licence keys/activation details for whatever commercial software you run — needed to reactivate on replacement hardware.
A backup that has never been restored is a hope, not a plan. The only way to know a backup will work when you need it is to have already proven it once:
- Restore the backup to a different machine or a test VM — not back onto the original, which proves nothing about whether the backup is independently usable.
- Confirm mail data opens and is searchable, not just that the files copied without error.
- Confirm the restored server can actually send and receive test mail with its configuration intact.
- Time how long the restore took — that number is your real recovery time, not the number on the backup software's marketing page.
- Repeat this periodically. Software upgrades, format changes, and configuration drift can quietly break a restore process that worked a year ago.
Backup frequency and restore speed should be driven by a real answer to "how long can this business function without email," not by whatever the backup software defaults to. A few practical questions:
- Is a nightly backup acceptable, or does losing a day of mail matter enough to need something closer to continuous replication?
- Is there a second machine (even a cheap spare) that could take over quickly, or does recovery mean provisioning new hardware from scratch first?
- If the server is down, does inbound mail queue at the sending server and retry (most legitimate mail servers retry for a period, typically measured in hours to a few days) or does it bounce immediately? This affects how much pressure you are actually under.
- Who has the DNS access needed to point mail at a temporary or replacement server if the original hardware cannot be recovered quickly?
An independent archive — a separate copy of mail as it flows, kept outside the live mailbox store — is a useful complement to backup, not a replacement for it:
- If the live server is lost entirely, an archive that captured mail on the way in and out can often recover more recent messages than the last backup, since it was written continuously rather than at the last backup interval.
- An archive protects against a category of loss backup does not: a user deleting mail, or the mail server's own retention policy expiring it, before the next backup even runs.
- It does not, by itself, restore a working mail server — that is still the job of a proper backup and restore process.
Hexamail Server stores mail and configuration in a form that can be backed up with standard file-level or VM snapshot tools, and documents what to include in a backup set. Hexamail Vault runs as an independent archive alongside your live mail server — capturing mail on the SMTP path as well as indexing mailboxes and PST files — so a recent copy of mail exists outside the live server even between backup windows. Vault is a complement to your backup plan, not a substitute for testing a real restore.