3-2-1 Backup: The Rule For Recovery
A single backup is not enough
You think you have a backup, so you are covered, right? Not even close. Having a backup of your emails is a must. However, it may not be enough. Several incidents show that some disaster could happen even if you backup your data regularly.
Doug Hazelman mentions the story of Pixar almost losing Toy Story 2 “because of a rogue command and failed backups. This was a film with a $90 million budget, one that would eventually gross more than $485 million at the box office. Pixar was saved only because someone had saved a third copy of the movie (data) offsite — on her home computer!“
The solution is the “3-2-1 Backup Rule”. The term was coined by Peter Krogh, a photographer, and it says that organizations should make three copies of their data available on two different media, with one stored offsite.
Applying the 3-2-1 rule to emails
You have a mail server either on-premise or in the cloud. Make a regular backup of the mail server, and configure email journaling letting the mail server copy each received email to an email archive hosted in a different datacenter or even in the cloud. Such setup gives you three copies, three different media, and one of the copies offsite.
You have several choices to achieve that. You may transport one backup copy to an offsite location. You may upload it to a cloud based storage like AWS S3 or Glacier. Having a cloud based or SaaS email archive already meets this criteria.
What if you are using O365, Google Workspace or some other cloud based mail provider? The 3-2-1 backup rule still applies. O365 and the others surely make backups of their data. However, you can and should still use email archiving to have the 3rd copy and the offsite backup criteria met.
Wouldn’t it make sense to use the email archiving services of O365 or Google? You may, however such setup misses the one copy offsite criteria from your perspective. Not to mention their poor level of archiving capabilities compared to a full featured email archive.
Do you need exactly three copies? No. Three is the minimum, but you can have more. Amazon stores several copies of the uploaded files to S3 to provide durability of 11 9’s (Actually 99,999999999% is their promise).