Each node canister in a system contains a battery that provides sufficient power to the node canister to allow an orderly shutdown in the event of a loss of power from the electrical utility.
The battery is maintained in a charged state by the battery subsystem. In this state, the battery can save critical data and state information in two back-to-back power failures. This means that the node canister can start immediately after the first power failure without waiting to recharge. After rebooting, if the battery does not have enough charge for a node to save its internal state, the node remains in service until the battery is charged sufficiently. If the power to a node fails, the node can write its configuration state and cache state to its internal drive using the power provided by the battery.
The battery system supports a 500 milliseconds ride-through capability to handle a brief AC power outage of up to 500 milliseconds. During this ride-through phase, the node can withstand these brief power outages and can remain available to service host I/O requests. If AC power is restored within the ride-through period, the node continues running normally and does not initiate any hardened (cache) data or state saves.
To access information about the battery in the management GUI, select . On the System - Overview page, click the directional arrow next to the enclosure that contains the battery module. Select Battery Module under Internal Components to display information about the battery module. To display information about the battery in the command-line interface, use the lsenclosurebattery command.