Understanding battery operations of a SAN Volume Controller node

The SAN Volume Controller nodes contain two replaceable battery units. Certain node models contain two replaceable battery units.

Although the node can run with a single battery, two batteries are needed to achieve redundancy. The node that runs on one battery is considered degraded and a node error is displayed until the missing or failed battery is replaced.

Do not remove a battery from a powered on node, unless one of the following conditions is met:

You are instructed to remove the battery by a fix procedure.
You verify that the battery is safe to be removed by using the service assistant GUI or the command-line interface.
The node is in service state or candidate state.
The battery fault LED is on or blinking.

If none of these conditions is met, then the node could go into service state or power off when a battery is removed.

The node has LEDs indicators that indicate the state of the battery:

Battery Status LED

The status of the battery backup system is indicated by the green battery status LED with the battery symbol. The green battery status LED indicates one of the following battery conditions.

Off: The software is not running on the node or the state of the system cannot be saved if power to the node is lost.
Fast blinking: Battery charge level is too low for the state of the system to be saved if power to the node is lost. Batteries are charging.
Slow blinking: Battery charge level is sufficient for the state of the system to be saved once if power to the node is lost.
On: Battery charge level is sufficient for the state of the system to be saved twice if power to the node is lost.

Battery fault LED

A fault with a battery is indicated by the amber battery fault LED on the battery unit. Each battery unit has a battery fault LED. The amber battery fault LED indicates one of the following battery conditions:

Off: The software is not running on the node or this battery does not have a fault.
Blinking: This battery is being identified.
On: This battery has a fault. It cannot be used to save the system state if power to the node is lost.

Identify the battery by its fault LED blinking. Activate the battery fault LED by using the command-line interface (CLI) or the management GUI.

If power loss occurs and is less than 5 seconds, the node retains power as if power was never lost. If the power loss exceeds 5 seconds all critical data on the node is saved and the node reboots when you save the critical data completes.

If a boot drive fails on a node, two functional batteries are required to complete a single configuration dump.

As a battery ages, it loses capacity. When a battery can no longer provide protection for two configuration dumps, the battery is marked end of life, and it needs replacement. Each battery requires a reconditioning cycle to ensure that it can maintain the expected charge over time. This reconditioning cycle is a series of discharge, relax, and charge operations that allow the battery capacity gauge to be calibrated to ensure its accuracy. The reconditioning cycle is only performed if the batteries are in a fully redundant system and is automatically scheduled approximately every three months. If the node loses redundancy, this reconditioning ends and is reattempted after redundancy is restored.