How does VC assign boot modes?
As part of processing a newly installed server, VC reads information from the system BIOS to determine if the server is UEFI capable or not. This information is stored until the profile is assigned. A new server profile setting is added to let the customer decide if a server should boot in UEFI mode or Legacy mode. This setting is only applicable for UEFI servers.
The basis on which the Customer decides whether to boot in UEFI or in Legacy Boot Mode can be any of the below following reasons:
•Functionality requiring UEFI
•Up gradation of existing resources
•OS installation
•Boot Considerations
•Customer needs in the data center
Once the profile is applied after choosing the boot mode, VC writes the boot order EVs (Environment Variables) while the server is paused from booting. This happens after the POST
On Legacy BIOS based systems, remote management software polls the server for an End of POST (EOP) event as an indicator that the BIOS has finished going through POST. This is necessary to safely read current BIOS configuration EVs, and then write them. A typical scenario would be to change the BIOS boot order after an EOP, and then reboot the server.
HP ProLiant Gen8 servers support a special EV used by Virtual Connect to instruct the BIOS to delay for a specified number of seconds after EOP has been signaled, but before rebooting the server. This allows software enough time to read and modify the BIOS settings, including changing the boot order.
The following diagram illustrates the boot sequence on HP ProLiant Gen8 servers.
RBSU is a configuration utility embedded in HP ProLiant servers that performs a wide range of configuration activities that include the following:
•Configuring system devices and installed options
•Enabling and disabling system features
•Displaying system information
•Selecting the primary boot controller
•Configuring memory options
•Language selection.
On UEFI based servers, the End of POST does not occur until a real OS is booted. This does not happen on bare metal systems, where a production or service OS has not been installed yet.
Software that needs to poll End of POST will have to instead use a new signal called POST Discovery Complete.
