Restart and power down a system with logical partitions

Understand how to safely restart and power down a system with logical partitions.

At times you will need to perform an initial program load (IPL) or power down the entire system or a single partition.

It is important to remember that when you perform an IPL on the primary partition you are also performing an IPL on all the secondary partitions.

If you power down the primary partition, you will also power down any secondary partitions that are running. Unless you power down the secondary partitions before the primary partition, any secondary partitions that are still running may have an abnormal IPL.

Refer to Basic system operations for more information on abnormal IPLs.

Some of the IPL tasks you can perform are as follows:

• Change a logical partition power schedule
• Change the time on a primary partition.
• Power down the system.
• Restart the system.
• Change operating mode for a logical partition.
• Change the IPL source for a logical partition.
• Restart a secondary logical partition during a system restart.
• Prevent a secondary logical partition from restarting during a system restart.

• Change logical partition power schedule
  You can schedule when a secondary partition will power on and power off by changing the IPL Date and Time (QIPLDATTIM) system value. You can change the QIPLDATTIM system value in Management Central in iSeries™ Navigator.
• Change the time on a primary partition
  When changing the time on the primary partition, verify that all secondary partitions are powered on. This will ensure that the configuration data for each secondary load source is updated appropriately.
• Power down a system with logical partitions
  The proper way to power down a secondary partition is by using the i5/OS™ power down system (PWRDWNSYS) command.
• Restart a system with logical partitions
  To restart the whole system (perform a power down and an initial program load (IPL)) the secondary partitions must power down with the primary partition.
• Change the operating mode for a logical partition
  The operating mode for logical partitions works just like operating mode on a system without logical partitions.
• Change the IPL source for a logical partition
  You can choose a separate initial program load (IPL) source (type) for each logical partition.
• Restart a secondary logical partition during a system restart
  
• Prevent a secondary logical partition from restarting during a system restart
  When you select this option the logical partition will not start when you perform a system (primary partition) restart or initial program load (IPL).