How to Send a Database Backup Off-Site

སྤྱི་ལོ་༢༠༢༦ ཟླ་བརྒྱད་པ་ ཚེས་ ༡༠

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Dump, compress, checksum, encrypt, transfer, verify. A six-step routine for getting a database backup to another location without exposing credentials.

To send a database backup off-site: dump it, compress it, record a checksum, upload it to an encrypted transfer with a short expiry, and have the recipient verify the checksum before you delete your copy. The verification step is the one people skip and the one that matters.

1. Dump

Take a consistent dump rather than copying data files from a running server. For MySQL that means mysqldump --single-transaction on InnoDB; for PostgreSQL, pg_dump. A copy of a live data directory is not a backup, it is a coin flip.

2. Compress

SQL dumps are text and compress extremely well — an 80% reduction is routine. gzip is fine and universally available; zstd is considerably faster at similar ratios if both ends have it. This step often turns a 40 GB transfer into an 8 GB one, which is a better speed-up than any tuning.

3. Checksum before you send

sha256sum backup-2026-08-23.sql.gz > backup-2026-08-23.sha256

Send the checksum through a different channel than the file. It is the only way either party can prove the backup that arrived is the backup that left.

4. Transfer with an expiry

A database backup is the single most sensitive file most organisations produce. It should not live on an open link indefinitely. Upload it with encryption enabled, set a password, and set the expiry to the shortest window the recipient can realistically work within — after which the file is deleted from storage automatically.

5. Verify on arrival

The recipient re-computes the checksum and compares. Only then does the sending side delete its copy. Enable download notifications so you know the moment it has been collected.

6. Do not email credentials alongside it

If the dump requires a decryption key, that key travels separately. A password in the same email as the link protects nothing.

Size expectations

A compressed dump of a mid-size production database usually lands between 2 GB and 50 GB. TeraSender handles single files up to 25 GB and transfers up to 1 TB, so a routine off-site copy fits comfortably — and the upload resumes if the connection drops partway through.