Often we need to secure communication channels, not for remote workers, but for server-to-server communication. Backups, for example, come to mind. It may be fine to use SSH or stunnel to ship data securely, but when performance is required and encryption cannot slow down communication, something else is necessary. OpenVPN is easy to configure, but it may not be sufficient.
If data is critical enough to ship off-site in real time, chances are it's valuable data, and should be encrypted for transit. Real-time data replication that databases often use, requires a fast enough network connection to avoid slowing down the local server. Disk block replication, i.e. DRBD, is even more sensitive to overhead when running synchronously to guarantee data integrity. Administrators will often configure a quick VPN connection for security, but then realize they've just compromised performance.

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