None of the three is safest alone, because each fails differently. An external SSD is fast and cheap but depends on someone plugging it in, and it sits next to the computer it protects. A NAS backs up every machine automatically and restores quickly, but it is in the same building. Cloud backup survives the loss of the office and needs no hardware, but restoring a large amount of data is limited by your internet line, and the bill grows with the data. The safest arrangement for a business uses two of them: a NAS on site for fast, automatic, everyday recovery, and a cloud or off-site copy for the day the site itself is the problem. An external SSD is a useful extra, not a strategy.
How do the three compare?
| External SSD | NAS | Cloud backup | |
|---|---|---|---|
| Up-front cost | Low | Moderate: unit plus drives | None |
| Ongoing cost | None | Power, drive replacement | Subscription, rising with data and users |
| Automatic | Only while connected | Yes, scheduled for all machines | Yes |
| Covers many computers | One at a time | Yes, centrally | Yes |
| Restore speed, large data | Fastest | Fast on the local network | Limited by internet speed |
| Survives a drive failure | No | Yes, with RAID | Yes |
| Survives fire or theft at the office | Only if kept elsewhere | No, unless replicated | Yes |
| Ransomware resistance | Poor if left connected; good if unplugged | Good with protected snapshots | Good with versioning and immutability |
| Version history | Depends on software | Yes | Yes, within plan limits |
| Data location | With you | On your premises | Provider's data centres |
| Depends on | Human routine | Your hardware and its upkeep | Provider, account security, internet |
How fast can you get data back?
CALC. Restoring 500GB:
| Source | Working speed | Time |
|---|---|---|
| External SSD over USB | about 400 MB/s | 500,000 / 400 = 1,250 s, about 21 minutes |
| NAS over 2.5GbE | about 280 MB/s | 500,000 / 280 = 1,786 s, about 30 minutes |
| NAS over 1GbE | about 110 MB/s | 500,000 / 110 = 4,545 s, about 76 minutes |
| Cloud over a 500 Mbps line | about 62 MB/s | 500,000 / 62 = 8,065 s, about 2.2 hours |
| Cloud over a 100 Mbps line | about 12 MB/s | 500,000 / 12 = 41,667 s, about 11.6 hours |
These are typical working speeds, and cloud restores are often slower than the line allows because of provider limits and many small files. For a single lost document the difference is irrelevant. For a whole server or a multi-terabyte share, it decides whether the office is working again today or next week. Some providers will ship a drive for very large restores; ask before you need it.
Where does each one fail?
- External SSD. The backup stops the week someone forgets, leaves, or leaves the drive in a drawer. If it stays plugged in, it is lost in the same fire, theft or ransomware attack as the computer. A single drive has no redundancy, and SSDs can fail without warning; see your SSD could lose data without warning.
- NAS. Everything is on site. RAID is not a backup of the NAS. A NAS exposed to the internet or run with weak passwords is a target in its own right.
- Cloud backup. Slow bulk restores, recurring cost, retention limits that may be shorter than you assume, and total dependence on account security. A stolen administrator login can delete cloud backups too unless immutability is enabled. Consider where the data is held and any obligations on transferring personal data overseas.
Note that a sync service is not a backup service. A synchronised folder copies deletions and encrypted files to every device. See why Microsoft 365 is not your complete backup strategy.
Ask of each backup: what single event would take out both this and the original? If the answer is a power surge, a thief or one password, you have found the gap.
Which combination suits which business?
| Business | Sensible combination |
|---|---|
| Sole proprietor, one laptop | Cloud backup, plus an external SSD kept unplugged between weekly backups |
| Office of 5 to 30 | NAS backing up all PCs and the file share, replicated to cloud or a second NAS off site |
| Large files: video, CAD, AI datasets | NAS with fast networking on site; off-site NAS or appliance for the second copy, since cloud restore would be too slow |
| Mostly Microsoft 365 or Google Workspace | Independent backup of the cloud data to a NAS or a third-party service |
| Regulated or highly confidential data | On-premises NAS and off-site appliance under your control, with protected snapshots |
On cost, a NAS is an up-front purchase that usually works out cheaper than per-user cloud subscriptions over a few years for teams with a lot of data; we run the numbers in NAS vs cloud storage costs for Singapore SMEs. The rule that ties the combinations together is in the 3-2-1 backup rule.
Buying in Singapore
On-site backup NAS: the Synology DS425+ (S$853.20), DS925+ (S$1,260) or DS1825+ (S$2,148), with Seagate IronWolf Pro drives from S$390. Off-site second copy on your own hardware: the Synology ActiveProtect DP320 (S$2,611.20). Power protection: the APC Back-UPS Pro BR 900VA (S$452.50) (listed 12 Nov 2026; prices change; ask for a current quotation). To start, use Request for Quotation on the product page, call (65) 6978 3502, email Sales@sourceit.com.sg or use our contact page.
Frequently asked questions
Which is safest: NAS, cloud backup or an external SSD? No single one. The safest setup combines an on-site NAS for fast automatic backups with a cloud or off-site copy that survives loss of the office.
Is an external SSD a good business backup? As an extra copy, yes. As the only backup it is weak, because it depends on someone connecting it, has no redundancy and is usually kept beside the computer.
Is cloud backup slower to restore than a NAS? For large amounts of data, usually yes. Restore speed is limited by your internet connection, while a NAS restores over the faster local network.
Is cloud sync the same as cloud backup? No. Sync mirrors changes, including deletions and encrypted files, to every device. Backup keeps independent versions you can restore from.
