IBM 71413SU Technical Reference - Page 30

Intelligent transportable battery backup unit (iTBBU) installed in the PCI slot spacer DIMM with RAID hardware Figure 14 ServeRAID-MR10k installed The use of ServeRAID-MR10k SAS RAID controller enables the following RAID levels: RAID-0 RAID-1 RAID-5 RAID-6 RAID-10 RAID-50 RAID-60 Note: RAID-50 and RAID-60 are only supported externally because they require a minimum of six or eight drives, respectively. The ServeRAID-MR10k supports stripe sizes from 16 KB to 1024 KB. The default stripe size is 256 KB. The ServeRAID-MR10k attaches by a short cable to an external intelligent transportable battery backup unit (iTBBU) which has the following characteristics: Intelligent: The iTBBU has built-in functionality to charge the battery pack automatically and to communicate battery status information such as voltage, temperature, and current to the server. Transportable: The iTBBU can be used to move a RAID DIMM's cached data to a replacement DIMM if that data has not been written to a disk. This could be necessary if, for example, the DIMM fails after an unexpected power failure. After you install the iTBBU on the new RAID DIMM, it flushes the unwritten data preserved in the cache to the disk through the new DIMM. The battery is designed to up to 72 hours cache protection, depending on operating environment. IBM recommends that the battery be replaced annually. The FRU part number for the replacement battery is 43W4283. Observe the following when using RAID or installing the ServeRAID MR10k: No rewiring of the existing internal cabling is required when the ServeRAID-MR10k is installed in an x3850 M2 or x3950 M2. 30 IBM System x3950 M2 and x3850 M2 Technical Introduction