Backup services and drives: what to compare

Choosing between cloud backup and an external hard drive is one of the most common backup questions, and the honest answer is that they do different jobs, so the question often ends up as “both”. A cloud backup service copies files over the internet to a provider’s servers, away from the home or office. An external drive keeps a copy on a device you can hold, unplug and put in a drawer. This guide starts with the backups already built into phones and computers, then explains when a drive or service adds something, how SSDs and hard drives differ, and how six widely available services and drives compare on their makers’ published specifications.

Do you need a backup product?

The Australian Signals Directorate’s ACSC describes a backup as “a digital copy of your most important information”, saved “to an external storage device or to an online server like the cloud”. It’s what lets photos, documents and records survive a dead laptop, a lost phone, an accidental deletion, a fire or flood, or a ransomware attack. The ACSC’s ransomware page warns: “If you don’t have a backup, it could be impossible to recover your files.”

For many people, the features already built into their phone and computer cover the basics. The ACSC says automatic backups can be set up “in your system or application settings”. The main built-in options, as their makers describe them:

• iCloud Backup (iPhone and iPad). Apple says automatic backups happen when Back Up This iPhone is on and the device is connected to power and Wi-Fi with the screen locked. If iCloud storage runs out, Apple’s page describes the option to buy more.
• Android backup. Google says some backed-up data “is end-to-end encrypted with your device’s screen lock PIN, pattern or password”, and that photos and videos are kept in Google Photos. Google also says that if a device isn’t used for 57 days, its backup (except photos and videos) is erased.
• Windows Backup and OneDrive. Microsoft says Windows Backup can back up the Desktop, Documents, Pictures, Videos and Music folders, plus settings and a list of installed apps. Folder backup works by syncing those folders to OneDrive, and Microsoft says a free Microsoft account comes with 5 GB of OneDrive storage.
• Time Machine (Mac). Time Machine backs up a Mac to an external disk, and Apple’s instructions include the option to encrypt that backup.
• Chromebook. Google says the Downloads folder is “a temporary folder” and that files there are sometimes deleted to clean up space, so saving to Google Drive keeps a copy online.

Step-by-step instructions for each are in our guide to the 3-2-1 backup approach for personal devices, and the backup readiness checklist helps track what’s covered.

When a drive or backup service adds something

The 3-2-1 rule

Microsoft’s backup guidance describes the 3-2-1 rule: “Have at least 3 copies of important files”, “On at least 2 kinds of media”, “And with at least 1 of them being physically located somewhere else”. In practice, that often means the original on the computer, a copy on an external drive, and a copy in the cloud. Built-in tools mostly cover one kind of media each: iCloud, Google and OneDrive are cloud; Time Machine is a local drive. That’s why the cloud-or-drive question often ends up as “both”.

Cloud sync is not the same as cloud backup

Cloud storage services such as OneDrive mainly sync files: change a file on one device, and the change appears everywhere. Microsoft explains that changes “will be automatically synchronized to the other location”. That’s convenient, but a deleted or ransomware-encrypted file can sync too.

Sync services increasingly add recovery features. Microsoft says its Restore your OneDrive feature lets Microsoft 365 subscribers undo actions from the last 30 days, for files that were “deleted, overwritten, corrupted, or infected by malware”.

A cloud backup service works differently. It copies files from the computer on a schedule or continuously, keeps earlier versions, and lets you restore a file as it was at an earlier point. Businesses using Microsoft 365 face a related question, covered in Microsoft 365 backup options.

Version history and ransomware recovery

Versioning means keeping older copies of a file, not just the latest one. If ransomware encrypts files and the encrypted versions get backed up, older versions are what make recovery possible.

The ACSC’s ransomware prevention guide says “the best recovery method from a ransomware attack is to restore from an unaffected backup”. It says backups should be used “only if you are confident that they are free from ransomware”, and not to connect a backup to the infected device or network. That’s one reason the 3-2-1 approach includes a copy that isn’t permanently connected, such as an external drive unplugged between backups. Our guide to how ransomware works and what limits the damage explains the threat.

What to compare

External drives: SSD or HDD?

A hard disk drive (HDD) stores data on spinning disks. A solid-state drive (SSD) uses flash memory and has no moving parts. On the makers’ published specifications for the drives below:

• the portable HDDs list the largest capacities (WD lists up to 6 TB; Seagate up to 5 TB)
• the portable SSDs list much higher speeds (Samsung lists read speeds up to 1,050 MB/s; Sandisk up to 2000 MB/s) and drop ratings (Samsung up to 2 metres; Sandisk up to 3 metres)
• all four list some form of password protection with encryption.

Encryption options for backups

A lost backup drive is a privacy risk, because it holds the same personal information as the original. The options the makers describe:

• Time Machine. Apple’s instructions include a step to “choose whether to encrypt backups” and set a password. Apple notes that if an unencrypted backup already exists on a network disk such as a Time Capsule, Time Machine must erase it before starting an encrypted backup.
• BitLocker. Microsoft says BitLocker Drive Encryption is available on Windows Pro, Enterprise and Education, not Windows Home. Removable drives appear under “BitLocker To Go”. Our guide to encrypted USB drives and storage explains this further.
• Drive makers’ software. Samsung, Sandisk, Seagate and WD each describe password protection with encryption.
• Cloud services. Backblaze and IDrive both describe an optional private encryption key. IDrive says it can’t recover a forgotten private key, so the data can’t be restored without it.

The checklist

• What it backs up. Whole computer, selected folders, phones, external drives, or network storage. Backblaze, for example, says it doesn’t back up NAS devices or flash drives.
• Version history. How long, or how many, earlier versions are kept.
• Restore options. Web download, app, or a physical drive posted out for large restores.
• Encryption and keys. Whether a private key is offered, and what happens if it’s forgotten.
• Account security. Whether two-factor authentication is available.
• For drives: capacity, speed, durability and warranty.
• Compatibility. Some drives may need reformatting for Mac or Windows.
• Cost over time. Plans and prices change; the maker’s site has current terms.

How the products compare

Based on makers’ published specifications, checked October 2026. Listed alphabetically, not ranked.

Cloud backup services

Portable drives

Detailed facts and considerations for each product appear in the summaries on this page.

How to set up a backup

Setting up a backup generally follows the same pattern:

1. Decide what matters most, such as photos, documents and business records.
2. Turn on the built-in backup for each phone and computer.
3. Add a second kind of media: an external drive, a cloud backup service, or both.
4. Turn on encryption and record the password or key somewhere safe and separate.
5. Test a restore. Microsoft calls testing “critical” and describes backing up a test file, deleting it, and restoring it “once a quarter, or maybe twice a year”.

How to encrypt a Time Machine backup

Based on Apple’s instructions (checked October 2026). Menus can change; Apple’s guide has the latest steps.

1. Open System Settings, then General > Time Machine.
2. Click Add Backup Disk and choose the external disk.
3. Click Set Up Disk, choose whether to encrypt backups, then click Done.
4. If asked to erase the disk, confirm or choose another one. Apple warns that “Erasing permanently removes all files on the disk.”
5. If encryption was chosen, type a password for the backup disk.

Things to watch for

• A drive that’s always plugged in. The ACSC says not to connect a backup to an infected device, and our 3-2-1 guide explains why an offline copy matters.
• Forgotten keys and passwords. With a private key or drive password, losing it can mean losing access to the backup.
• Exclusions. Cloud backup services may skip some drives or file types; their documentation lists what’s left out.
• Inactive backups. Google says Android backups (except photos and videos) are erased after 57 days of not using the device.
• Free storage limits. Microsoft lists 5 GB of OneDrive storage with a free Microsoft account, and Apple’s page describes buying more iCloud storage when a backup doesn’t fit.

Common questions

Is cloud backup better than an external hard drive?

Neither is simply better: they protect against different things. A cloud backup service copies files over the internet to a provider’s servers, away from the home or office, while an external drive can be unplugged and kept offline. Microsoft’s 3-2-1 rule refers to at least two kinds of media, with one copy somewhere else, which is why the question often ends up as “both”. See the 3-2-1 rule.

Is an SSD or HDD better for backups?

It depends on what matters most. A hard disk drive (HDD) stores data on spinning disks; a solid-state drive (SSD) uses flash memory and has no moving parts. On the makers’ published specifications compared here, the portable HDDs list larger capacities, while the SSDs list higher speeds and drop ratings. All four drives list password protection with encryption. See SSD or HDD and the comparison table.

Do I need a cloud backup service if I have iCloud or OneDrive?

Built-in services may be enough for many people, depending on what they want covered. Microsoft describes OneDrive folder backup as syncing, so a deleted or ransomware-encrypted file can sync too, and lists a 30-day Restore your OneDrive feature for Microsoft 365 subscribers. Dedicated backup services describe keeping earlier versions; Backblaze lists 30 days by default, extendable. See sync versus backup.

What is the 3-2-1 backup rule?

Microsoft describes the 3-2-1 rule as at least 3 copies of important files, on at least 2 kinds of media, with at least 1 physically located somewhere else. In practice that often means the original on the computer, a copy on an external drive, and a copy in the cloud. Built-in tools mostly cover one kind of media each. See the 3-2-1 rule and our 3-2-1 guide for personal devices.

Can a backup help me recover from ransomware?

It can, according to the ACSC, which says “the best recovery method from a ransomware attack is to restore from an unaffected backup”. It also says to use backups only once confident they’re free from ransomware, and not to connect a backup to the infected device or network. The ACSC’s 24/7 hotline is 1300 CYBER1 (1300 292 371). See version history and ransomware recovery.

How do I encrypt a Time Machine backup?

Encryption is chosen when setting up the backup disk. In Apple’s steps: open System Settings > General > Time Machine, click Add Backup Disk, choose the disk, click Set Up Disk and choose to encrypt backups, then type a password. Apple warns that erasing a disk permanently removes all files on it, and a forgotten password can mean a backup can’t be restored. The full steps are above.

Where to get official help

• ASD’s ACSC: set and perform regular backups
• ASD’s ACSC: ransomware, and the 24/7 hotline 1300 CYBER1 (1300 292 371)
• Microsoft: back up and restore with Windows Backup
• Apple: Time Machine backup disk and encryption options