Memory state and reboot
On a running Linux® instance, memory hotplug can
change the online state of memory blocks for both hotplug memory and core memory. For core memory,
the state is always preserved across boot cycles.
Depending on multiple conditions, the state of hotplug memory might be reset to offline.
Booting with memory clearing
With memory clearing, an IPL or re-IPL resets all hotplug memory to offline.
Exception: The online status of hotplug memory is preserved for Linux on z/VM® after a
regular shutdown with a subsequent IPL from a CCW device.
Booting without memory clearing
Without memory clearing, the status of hotplug memory after an IPL or re-IPL depends on the type
of IPL device:
- For CCW IPL devices the state is preserved.
- For FCP-attached IPL devices and for PCIe-attached NVMe IPL devices the state is reset to offline.
Reboot without memory clearing is the default. To force memory clearing, configure your re-IPL device with the clear option, see Rebooting from an alternative source.