![](/images/new-backgrounds/1108832/10883267x1.webp)
Note: Some memory is reserved for various system resources and is unavailable to the operating system. The amount of memory that is reserved for system resources depends on the operating system, the configuration of the server, and the configured PCI options.
Turning off the server
When you turn off the server and leave it connected to ac power, the server can respond to requests from the IMM, such as a remote request to turn on the server. While the server remains connected to ac power, one or more fans might continue to run. To remove all power from the server, you must disconnect it from the power source.
Important: To view the error LEDs on the system board, leave the server connected to a power source.
Some operating systems require an orderly shutdown before you turn off the server. See your
Statement 5
CAUTION:
The power control button on the device and the power switch on the power supply do not turn off the electrical current supplied to the device. The device also might have more than one power cord. To remove all electrical current from the device, ensure that all power cords are disconnected from the power source.
The server can be turned off in any of the following ways:
vYou can turn off the server from the operating system, if your operating system supports this feature. After an orderly shutdown of the operating system, the server will be turned off automatically.
vYou can press the
vIf the operating system stops functioning, you can press and hold the
vThe IMM can turn off the server as an automatic response to a critical system failure.
vYou can turn off the server through a request from the IMM.
20IBM System x3850 X5 and x3950 X5 Types 7145, 7146, 7143, and 7191: Installation and User's Guide