IBM 71413SU - System x3950 M2 Reference

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30 IBM System x3950 M2 and x3850 M2 Technical IntroductionFigure 14 ServeRAID-MR10k installedThe 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-60The ServeRAID-MR10k supports stripe sizes from 16 KB to 1024 KB. The default stripe sizeis 256 KB.The ServeRAID-MR10k attaches by a short cable to an external intelligent transportablebattery backup unit (iTBBU) which has the following characteristics: Intelligent: The iTBBU has built-in functionality to charge the battery pack automaticallyand to communicate battery status information such as voltage, temperature, and currentto the server. Transportable: The iTBBU can be used to move a RAID DIMM's cached data to areplacement 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 iTBBUon the new RAID DIMM, it flushes the unwritten data preserved in the cache to the diskthrough the new DIMM.The battery is designed to up to 72 hours cache protection, depending on operatingenvironment. IBM recommends that the battery be replaced annually. The FRU part numberfor 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 isinstalled in an x3850 M2 or x3950 M2.Note: RAID-50 and RAID-60 are only supported externally because they require aminimum of six or eight drives, respectively.Intelligent transportablebattery backup unit (iTBBU)installed in the PCI slotspacerDIMM with RAID hardware