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3-2-1 Backup Rule for Data Protection in SQL – What Is It & Is It Relevant?

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In the event of a disaster leading to database unavailability, restoring backups is the first step to ensure business continuity. However, situations may arise when attempts to restore the database fails. For instance, the tape drive used for storing backups may get damaged rendering the backup data corrupt and unusable. In fact, tape drive media failure is the most common cause why restore fails. To prevent this and ensure database can be restored with uncorrupted data, SQL users implement the 3-2-1 backup rule for data protection. This article discusses this data protection rule and if it is still relevant.

The 3-2-1 Backup Rule for Data Protection – What It Is?

The 3-2-1 rule of data protection ensures that database can be restored with uncorrupted data. The idea behind the rule is to have:

3 copies of backup: You must have at least three copies of your data. One is your production data plus two backup copies. The more copies you have, the less risk you have of losing data.

2 copies on different media: Ensure to store two copies of database backup on different media types. This is important because a backup media can fail. When you split your backup into different media and a device fails, you’ll have another to fall back on.

1 copy on offsite: Store one of the two backups offsite. Doing so ensures that if anything happens to one backup copy, it won’t (hopefully) affect the other copy.

Is the 3-2-1 Backup Rule of Data Protection Relevant for SQL Users?

The 3-2-1 backup is a good starting point for devising any disaster recovery plan, particularly for SQL users who aren’t backing up at all. But, the backup rule has certain shortcomings.

Data Can Be Compromised

Maintaining three copies of data is fine, as more copies ensure recovery is possible in case of any disaster. But keeping two copies on different media types has limitations. Having two copies stored in two storage media or devices means quicker access to the backup (if the primary fails), however, this might not always be the case.

What happens if a ransomware infects your secondary storage while the primary is already down? You may lose all the data unless you pay a ransom. And, with several organizations replacing tape backup with cloud storage, an ever-increasing number of databases becoming vulnerable to ransomware attacks.

According a report by Imperva, “46% of all on-premises databases are vulnerable to attack.” Imperva predicted that data breaches will continue to grow as nearly one out of two on-premises databases is vulnerable to attacks. And so, you need more comprehensive and stronger data protection strategies than ever before.

Faulty Interpretation of the 3-2-1 Backup Rule

Backing up on tape drives is more expensive than backing up data on the cloud. And, as the demand for storage space grows so does the need for storage cost. Though, tape is still used – but due to slow recovery time and high cost involved – users are moving data to offsite locations, such as the cloud. That’s where the problem starts.

As cloud-based services not necessarily store backups at the same storage facility, point “2” and “1” in the backup rule are ignored. In other words, moving offsite data to cloud can fulfil the purpose of point “2” – it can be used to store a backup copy that is incorruptible and used for recovery if the first copy is affected. But this way, you’ll have only a single copy which doesn’t offer the protection you need from ransomware or other cyber threats.

Air Gap Protection is Lost

Though tape-based storage can slow down your recovery due to bandwidth constraints, it provides air gap to prevent ransomware from affecting your backup copies. However, air gap protection is missing in the 3-2-1 rule.

Air gap is basically a way of protecting a backup copy by storing it on a network that is physically separate from the primary data.

It was easy to provide an air gap when using tape backups. You can place tape backups in a box and transport them to off-site locations, creating an air gap between your backup and primary data copy. This makes it harder for hackers to attack a database, as they cannot attack both primary and backup storage devices.

How to Overcome 3-2-1 Backup Rule Shortcomings?

Backup strategies like 3-2-1-1-0 or 4-3-2 offers additional protection against ransomware attacks. Let’s discuss in brief about these two strategies:

3-2-1-1-0 Backup Rule

Like the ‘3-2-1’ backup rule, the 3-2-1-1-0 data protection strategy also requires maintaining at least three copies of data, storing data on at least two different storage media, and storing one backup copy offsite. Plus, it requires two additional steps:

  • Keeping one tape backup copy offline or air gapped, as it requires storing tape backups off-site. Or you may store cloud backups with immutability, thereby preventing data from getting modified or changed.
  • Monitors data to help identify and correct any errors in the backups.

Essentially, the 3-2-1-1-0 backup rule ensures that you've an error-free offline backup copy you can use to recover data in case of system failure or cloud failure.

4-3-2 Backup Rule

Developed by IT security partners, Continuity Centers, the 4-3-2 rule states that four copies of data are stored in three different locations. Out of the three locations, two are offsite and the third copy is stored in the cloud. And, the fourth backup goes to another cloud storage.

The 4-3-2 backup strategy ensures that duplicate copies of backups are created and stored at geographically distant locations to avoid data loss in the events of natural disasters.

Concluding Thoughts

Preventing data loss, in the event of a disaster, is crucial for business continuity. And so, you must be regularly taking backups and reviewing them to ensure their effectiveness in restoring the SQL databases. The 3-2-1 backup rule is a good starting point for data security, but you need more extensive backup strategy to protect your data against the growing number of digital threats. Upgrading the 3-2-1 rule to a 3-2-1-1-0 or 4-3-2 backup strategy provides an additional layer of security to help you recover ransomware affected databases.

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