Friday, October 21, 2016

Ensuring ILOM power up on Exadata with IPMI

Like it or not, power interruptions are still a thread to servers. Even though servers ship with dual power supplies and if done correctly they should be plugged into different power supplies within the datacenter a power outage can still happen. Even tough datacenters should have backup power and provide uninterrupted power to your machines it still might happen. To ensure all your systems are behaving in the right way when power comes back on you can make use of some settings within the IPMI configuration.

The Intelligent Platform Management Interface (IPMI) is a set of computer interface specifications for an autonomous computer subsystem that provides management and monitoring capabilities independently of the host system's CPU, firmware (BIOS or UEFI) and operating system. IPMI defines a set of interfaces used by system administrators for out-of-band management of computer systems and monitoring of their operation. For example, IPMI provides a way to manage a computer that may be powered off or otherwise unresponsive by using a network connection to the hardware rather than to an operating system or login shell.

Oracle Servers have IPMI on board and it is good practice to ensure you make use of the HOST_LAST_POWER_STATE information to ensure your server boots directly when power comes back online or is not booting up when the server was already down during the power outage.

To verify the ILOM power up configuration, as the root userid enter the following command on each database and storage server:

if [ -x /usr/bin/ipmitool ]
then
#Linux
ipmitool sunoem cli force "show /SP/policy" | grep -i power
else
#Solaris
/opt/ipmitool/bin/ipmitool sunoem cli force "show /SP/policy" | grep -i power
fi;

When running this on an Exadata the output varies by Exadata software version and should be similar to:

Exadata software version 11.2.3.2.1 or higher:
HOST_AUTO_POWER_ON=disabled
HOST_LAST_POWER_STATE=enabled

Exadata software version 11.2.3.2.0 or lower:
HOST_AUTO_POWER_ON=enabled
HOST_LAST_POWER_STATE=disabled

If the output is not as expected you will have to ensure make the settings correct so your Exadata machine boots directly after the power is restored. 
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