120 Planning, Installing, and Managing the IBM System x3950 M2To hot-swap a failed DIMM:1. Verify that memory mirroring and hot-swap are enabled by checking thememory hot-swap enabled LED on the memory cards.When a DIMM fails, you are alerted with the memory LED on the light pathdiagnostics panel and by other means with the service processor, if this hasbeen configured.2. Locate the memory card that has the failed DIMM by identifying whichmemory card has the lit memory error LED.3. Remove the memory card containing the failed DIMM.4. Press the button on the memory card to identify which DIMM has failed. TheLED next to the failed DIMMs light up.5. Replace the failed DIMM and reinsert the memory card.For details about hot-swapping memory correctly and which sequence to follow,see IBM: System x3850 M2 and System x3950 M2 User’s Guide:http://www.ibm.com/support/docview.wss?uid=psg1MIGR-50730293.2.5 Hot-add memoryThe hot-add memory feature enables you to add DIMMs without turning off theserver. This setting can be changed as described in 3.2.6, “Memory configurationin BIOS” on page 121.Requirements for enabling the hot-add memory feature on the server are: The operating system must support the adding of usable system memory to arunning operating system. This is done with an ACPI sequence.Currently, the only operating systems that have this capability and support onthe x3850 M2 and x3950 M2 are Windows Server 2003 and Windows Server2008, both Enterprise Edition and Datacenter Edition. Memory hot-add must be specifically enabled in the BIOS setup. When this isdone, the system allocates blank windows of memory space for futurememory additions. By enabling hot-add, memory mirroring will automaticallybe disabled. Memory cards 2 and 4 must not be installed because these are the only cardsthat can be hot-added. If only one memory card, memory card 1, is installed prior to the hot-addoperation, then only one more memory card may be added in slot 2. If two memory cards are installed in slots 1 and 3, then two additional memorycards can be added in slots 2 and 4.
