What type of drive allows for replacement without shutting down the server?

The correct choice is hot swappable drives, which are designed to be inserted and removed from a server while it remains powered on without affecting its operations. This capability is particularly essential for maintaining high availability in environments where uptime is critical, such as data centers and enterprise systems. Hot swappable drives enable administrators to replace failing drives, upgrade storage capacity, or perform routine maintenance without incurring downtime, thus ensuring continuous access to data and applications.

In contrast, cold spare drives are not immediately usable and require the server to be powered down before they can be installed. Backup drives, while they serve as data redundancy tools, do not inherently provide the ability for replacement while the server is running. Data drives refer to drives that store data but do not imply any specific operational capability like hot swapping. Understanding these distinctions is crucial for implementing effective server management and ensuring system reliability.