Powering on and powering off the system

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To power on or to power off the system, complete the steps in this procedure in the order given.

Powering on the system

Important:
  • Do not power on a node that is shown as offline in the management GUI, if you powered off the node to add memory to increase total memory. Before you increase memory, you must remove a node from the system so that it is not showing in the management GUI or in the output from the lsnode command.
  • Do not power on a node that is still in the system and showing as offline with more memory than the node had when it powered off. Such a node can cause an immediate outage or an outage when you update the system software.
  1. Power on the Fibre Channel switches.
  2. Power on external storage systems.
  3. Power on the nodes.
  4. Power on expansion enclosures.
  5. Start hosts.

Before you power off the system

To remove all input power to a system (for example, the machine room power must be shut down for maintenance), you must shut down the system before power is removed. Shutting down the system causes all nodes in the system to store data to the internal drive and then enter a standby state. In standby state, volumes that are provided by the system are no longer accessible.

If the system is not shut down before power to the nodes is turned off, the nodes detect the loss of power. The nodes continue to run on battery power until all data that is held in memory is saved to the internal drive.

When input power is restored to the enclosures, the batteries in the nodes recharge. However, the nodes do not allow any I/O activity until the batteries have sufficient charge. Sufficient charge is defined as being able to save all of the data that is on the nodes if an unexpected power loss occurs. Recharging might take 2 hours if the batteries are discharged because the nodes ran on battery power. Shutting down the system before removing input power to the batteries prevents the battery power from being drained and makes it possible for I/O activity to resume as soon as input power is restored.

Powering off the system

  1. Stop hosts.
  2. Shut down the system by using the management GUI. Click Monitoring > System. In the System Actions menu, select Power Off System.
    Note: You can use the front panel to shut down nodes individually; however, this method is not advisable. Some node models do not have a front panel display.
  3. Power off the expansion enclosure.
  4. Shut down external storage systems.
  5. Shut down Fibre Channel switches.
Important: Powering off a SAN Volume Controller 2145-DH8 node until possible the next day can drain the batteries. Follow these steps to prevent the batteries from being discharged too much while the node is connected to power but not powered on.
  1. Pull both batteries out of the node. Keep them out until you're ready to power on the node.
  2. Push the batteries in just before you press the power push-button to power on the node.
If you disconnect the power from a SAN Volume Controller 2145-DH8 node and might not reconnect power to it again within the next 24 hours, follow these steps to prevent the batteries from being discharged too much while the node is not connected to power:
  1. After both power cords are disconnected from the node, pull both batteries out of the node. This step completely turns off the battery backplane.
  2. Push the batteries back in again.