An existing Synology High Availability pair has two physical servers to protect. Seeing UPS support enabled in DSM does not establish that both power cables use battery-backed outlets or that the equipment carrying UPS status will remain powered. Review the wiring and configuration together before relying on the pair during an outage.

This check concerns a DSM 7 Synology High Availability cluster. Synology's cited setup guidance excludes its dual-controller NAS and Unified Controller models. Identify the actual hardware and software first; do not apply a diagram for two separate servers to a different storage architecture.

Draw power and communication separately

On a simple sketch, name the active host, passive host and each UPS. Trace every relevant power lead to its outlet. Synology specifically warns that some UPS sockets provide surge suppression without battery backup. Read the UPS labels and manual rather than assuming all sockets have the same purpose.

Next trace how UPS status reaches the servers. Include switches used by that communication path and record how those switches are powered. The HA help explains that switch power is part of the cluster's power planning. A running NAS cannot receive a network message through a switch that has lost power.

Compare the plan with DSM

Inspect Control Panel, Hardware & Power, UPS for both servers. Record the selected UPS arrangement and standby timing. Synology's single-UPS arrangement depends on both hosts receiving UPS power; its two-UPS guidance has different outcomes depending on which supply fails. Match the documented case to the sketch instead of expecting every outage to cause the same switchover.

Use this review to prepare a controlled maintenance test with the administrator and affected staff. Do not create an unplanned outage by pulling a production cable. Define which services may stop, how results will be observed and how normal power will be restored.

The resulting handover should identify uncovered outlets or network equipment, the relevant DSM settings and any test still outstanding. A wiring inspection is useful evidence, but it should remain distinguishable from a witnessed power-failure test and a checked recovery afterwards.

Sources: Synology documentation 1, Synology documentation 2.