Tandem - page sections

Continuity · Recording-Server Redundancy

Tandem

Active-Active. Two Recorders. One Identity.

Active-active recording-server redundancy for Milestone XProtect. Two machines record from the same cameras and present to XProtect as one logical recorder, so a server failure never leaves a gap in your video.

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Available October 1, 2026 Licensed per recorder pair Platform Milestone XProtect

Tandem recorder pair shown in normal operation and during failover

Beyond Standard Failover

Standard failover leaves two gaps. Tandem closes both.

The Problem · Standard Failover

A gap in recording, a hole in playback

When the primary recorder fails, the failover server starts recording from that moment, so video from the switchover window is lost. And while the primary is down, only footage on the failover server can be viewed. The primary's archived footage stays out of reach until it is restored.

The Tandem Difference

Nothing to rebuild, nothing to catch up

The headless recorder has been capturing the same cameras the whole time, so it never starts fresh at the moment of failure. There is no switchover gap, and the footage is already on disk and ready to serve. Recording and playback both continue without interruption.

How It Works

An attached and headless pair, acting as one.

A Tandem pair runs in an attached and headless arrangement. Both recorders continuously capture and record from the same cameras. Only the attached recorder connects to the Management Server and serves clients. The headless recorder records in parallel but serves no one until it is needed.

1Both record in parallel. Each recorder captures directly from the same cameras, at the same time.
2One serves clients. The attached recorder connects to XProtect and handles live and playback.
3The partner takes over. If the attached recorder fails, the headless recorder connects to the XProtect services and begins serving requests, with no rebuild and no catch-up window.

Tandem normal operation and failover architecture

What Tandem Does

Always in sync. Always ready.

Continuous Configuration Sync

Copies configuration from the attached recorder to the headless recorder on an ongoing basis. The pair stays identical, so the standby is always ready to take over with the current settings.

Media Resync on Recovery

When a recorder comes back online, Tandem copies the media it missed from its active partner. The media database is restored to a complete state, and both recorders again hold the full record.

Transparent to Third-Party Integrations

Failover is invisible to the software layered onto XProtect. Every identifier, name, and reference that PSIM, access control, and analytics depend on stays constant. Nothing is renamed, renumbered, or re-registered.

Built for XProtect

One logical recorder. Every integration intact.

Tandem is especially well suited to deployments where multiple third-party systems are integrated into XProtect. Because the pair presents itself as one recorder, the systems built on top of it never notice a failover.

Presents two machines to XProtect as one logical recorder
Identifiers, names, and references stay constant across failover
PSIM, access control, and analytics keep working without re-registration
Operators experience no interruption and need to do nothing

Availability & Licensing

Simple to size, simple to license.

Tandem is licensed per recorder pair. Two machines, physical or virtual, one license, one logical recorder.

Available October 1, 2026

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