IBM System x3850 X6 18The following rules apply when building a server configuration with eXFlash DIMMs:The 200 GB and 400 GB eXFlash DIMMs cannot be mixed.RAID 1 mirroring is provided by the eXFlash DIMM device driver.Performance memory mode must be selected. RAS (lockstep) memory mode is not supported.Only RDIMMs are supported by eXFlash DIMMs; LRDIMMs are not supportedThe maximum quantities of eXFlash DIMMs are as follows:One processor: 8 eXFlash DIMMsoTwo processors: 16 eXFlash DIMMsoFour processors: 32 eXFlash DIMMsoInternal storageThe server supports 1.8-inch solid-state drives in the IBM eXFlash SSD units and 2.5-inch SSDs andHDDs. Drives are installed in the Storage Book. The x3850 X6 has one Storage Book. The Storage Booksupports the following configurations:4x 2.5-inch hot-swap drive bays8x 2.5-inch hot-swap drive bays4x 2.5-inch hot-swap drive bays + 8x 1.8-inch hot-swap SSD bays8x 1.8-inch hot-swap SSD bays16x 1.8-inch hot-swap SSD baysThe following figure shows these configurations.Figure 6. Internal drive configurations