HP Netserver E Server series - Manual (Page 13)

Chapter 1 Controls, Ports, and Indicators
7
Connecting AC Power to Multiple-Server Configurations
The HP NetServer temporarily draws a large "inrush current," when first
connected to an AC power source. This also occurs when the NetServer is in a
standby mode (power is turned off, but the power cord is plugged into AC power).
The inrush current is much greater than the NetServer’s normal operating current
and generally, the AC power source can handle the normal inrush current.
However, if you install several HP NetServers on one circuit, precautions are
necessary. If there is a power failure and power is then restored, all the servers
immediately begin to draw inrush current at the same time. If the circuit breakers
on the incoming power line have insufficient capability, the breaker may trip and
thus prevent the servers from powering up.
When preparing your site for installation, allow for the additional inrush current.
Refer to Table A-1, "Power Supply Specifications" in Appendix A.
Sleep States (ACPI)
The HP NetServer supports the ACPI (Advanced Configuration and Power
Interface) standard, which is a key component of a NOS’s directed power
management. The supported features are only available when an ACPI-compliant
NOS is installed on the NetServer. The term "sleep state" refers to any of several
reduced power consumption states in which normal NOS activity has ceased.
The NetServer supports several sleep states, including a sleep state with a short
wake-up time, sometimes referred to as "standby" or "suspend" by various
operating systems. In this sleep state the NetServer appears to be off and is
indicated by no display on the monitor and no activity for the CD-ROM or
internal hard drives. However, the power LED is slowly flashing and the fans are
operating.
An additional sleep state supported by the NetServer is one with a slower wake-up
time, sometimes referred to as "hibernate" by various operating systems. In this
sleep state, the NetServer appears to be off as mentioned earlier, but the fans and
the power LED are also turned off. The unique feature of this sleep state (and the
reason for its slower wake-up time) is that the NetServer’s NOS state (applications
running, screens open, etc.) just prior to hibernate has been saved to disk and must
be restored from disk upon wake-up. However, this method of restoring the
NetServer’s operation is much faster than a complete rebooting of the NetServer.
This method still requires running all the start-up self-tests before starting the
NOS, but loading the NOS and all the previously opened applications is much
faster.