Storage and Backup Essentials

Internal SSDs, external drives and NAS devices solve different problems and are not interchangeable. An internal SSD is the drive inside a computer that the operating system and applications run from — its speed directly affects how fast the machine feels day to day. An external drive is portable storage for transferring files or making a manual backup copy, plugged in as needed rather than left running constantly. A NAS (network-attached storage) is a small always-on server that multiple computers on a network can save to and back up from automatically, making it the right tool for shared files and scheduled backups across a team rather than a single machine.

The 3-2-1 rule is the standard baseline for backup planning: keep at least 3 copies of important data, on at least 2 different types of media, with at least 1 copy stored off-site or disconnected from the main network. In practice for a small business this often means the working copy on a computer or server, a second copy on a NAS or external drive in the office, and a third copy either in cloud storage or on a drive that is physically kept elsewhere. The off-site or disconnected copy is what protects against theft, fire, or ransomware that can otherwise encrypt or delete backups that stay permanently connected.

Capacity should be chosen with headroom, not against current usage exactly. As a rule of thumb, buy 2-3x more capacity than your current data footprint to allow for growth over several years without needing to replace the drive immediately; for a NAS, also account for RAID overhead, since mirroring or parity configurations use some capacity for redundancy rather than storage. On interfaces, USB 3.0 or higher is the minimum for external drives — older USB 2.0 devices are noticeably slower for large file transfers — and NAS units should be connected over Gigabit Ethernet or faster, since Wi-Fi introduces a bottleneck for backup jobs involving large amounts of data.

Drive type is the last decision. SSDs (internal or external) are faster and more resistant to physical shock, making them the better choice for a working drive or a portable drive that travels; traditional hard disk drives (HDDs) remain more cost-effective per gigabyte for bulk, infrequently accessed backup storage, which is exactly the role a backup archive plays. Matching drive type to role — SSD for active work, HDD-based NAS or external drive for bulk backup — gets the best balance of speed, cost and reliability.