Cloud Backup vs On-site Backup Explained

Everyone agrees backups are important, right up until the moment one is needed. Then the only question that matters is whether your data comes back. The good news is that a sound backup approach is not complicated. It comes down to a simple principle and a couple of honest trade-offs.

The 3-2-1 principle

The most widely used rule of thumb in the industry is 3-2-1. It means:

• Keep at least three copies of your important data.
• Store them on two different types of media or systems.
• Keep one copy off-site, away from your premises.

The logic is straightforward. One copy can fail. Two copies in the same building can both be lost to the same fire, flood, theft or ransomware attack. Spreading copies across different systems and locations means no single event wipes out everything at once.

On-site backup: fast, but exposed

On-site backup keeps a copy of your data on hardware in your office, such as a network drive or backup appliance. Its big advantages are speed and control. Restoring a large file or a whole server from a device sitting in the next room is quick, and you are not dependent on your internet connection.

The weakness is that the backup lives in the same place as the thing it is protecting. A break-in, a burst pipe, a power surge, or ransomware that spreads across the network can take out both your live data and your on-site backup together. On its own, it does not satisfy the off-site part of 3-2-1.

Cloud backup: off-site by default

Cloud backup sends an encrypted copy of your data to a secure data centre over the internet. Because it is stored away from your premises, it naturally covers the off-site requirement, and it keeps working even if your office is out of action entirely.

The trade-offs are that restoring very large amounts of data depends on your internet speed, and there is an ongoing subscription cost. For most businesses those are minor next to the peace of mind of knowing a copy is always safely off-site.

For many, the sensible answer is not one or the other but both: an on-site copy for quick everyday restores, and a cloud copy for genuine disaster protection. That combination fits the 3-2-1 rule neatly.

The Microsoft 365 blind spot

Here is the part that catches a lot of businesses out. If your email and files live in Microsoft 365, it is easy to assume Microsoft backs everything up for you. Microsoft keeps its infrastructure highly available, but that is not the same as backing up your data.

Consider what Microsoft does not fully protect you from:

• A staff member permanently deleting emails or files, with the deletion syncing everywhere before anyone notices.
• An account being compromised and data destroyed by an attacker.
• Someone leaving and their mailbox or files being removed.
• Ransomware encrypting documents stored in OneDrive or SharePoint.

Microsoft's own service terms recommend using a third-party backup, and their retention windows are limited. Once that window passes, deleted data is generally gone for good. A dedicated Microsoft 365 backup keeps its own independent copy, so you can recover a mailbox, a document, or a whole account long after the fact.

The takeaway

Aim for three copies, on two kinds of storage, with one off-site, and do not assume the cloud has you covered by default, especially with Microsoft 365. If you are not certain your backups are complete or would actually restore, it is worth checking properly before you need them. Our team can review what you have and point out any gaps. Call Comsys IT on 0800 724 526.