Intel SR6850HW4 Product Guide - Page 41

The server BIOS also includes two additional memory reliability, accessibility, and serviceability (RAS) features: ƒ Memory Sparing: A rank on each memory board can be reserved as a "spare" and can only be used as a backup for other ranks on the same memory board. The memory rank that is configured as spare is held in reserve and cannot be used by the operating system. Hot removal cannot be performed when in a Memory Sparing configuration. When the error rate for a failing rank exceeds an established threshold, the contents of that rank are copied to the spare rank. At the completion of the copy, the failing rank is disabled and the spare is used in its place. This is called Memory Sparing. By enabling memory sparing, the total memory of each memory board is reduced by the largest DIMM rank installed on the memory board. This ensures that the any failing rank will fit on the spare rank. When the failing rank switches to the spare, the BIOS will turn on the memory board LED to indicate the bad DIMM. The failing DIMM is then disabled on subsequent system boots. ƒ Memory Hot Plug: This memory RAS feature provides the ability to hot-replace and hot-add memory boards while the system is running. This feature can be used to perform: - Memory Hot Replace: While the system is in operation, you can remove a failed memory board, provided it is in a RAID or Mirror configuration, and replace it with a board of the same memory capacity. The system will test, initialize, and rebuild the data on the memory board and then include this board in the system memory configuration. The activity is transparent to the operating system, - Memory Hot Add: You can increase the memory capacity of the system while the operating system is active. In a RAID or Mirror configuration, you can remove one memory board at a time to upgrade the memory or replace the memory board. In a Mirror configuration, you can add an addition two mirrored memory boards. In a Maximum Compatibility configuration, a new memory board can be added to an empty slot. When the initialization is complete, the OS is informed of the new memory.  NOTE Memory Hot Add must be supported by the operating system in order to perform this function. Check for an operating restrictions. 41