Well, yes, you can re-enable the S100, but just know that the S100 is a WINDOWS-ONLY controller.  Boot to BIOS Setup (F2), SATA Settings, set Embedded SATA to RAID. You should plan to get a battery ... they cost like $3.  Normally, the absence of a battery would not cause the system to fail, but if the server ever got unplugged or lost power, then all the BIOS settings would be reset to default.  So, if you had Embedded SATA set to ATA, for example, and you lost power, the system would have reverted to AHCI ... THAT could cause the OS to fail to boot due to driver-related settings. If you don't believe this caused your system to fail, then you need to provide more details, as I can't answer that with what little information has been provided. When you say the system failed, what do you mean?  Are you talking about hardware failure or software/OS failure?  Did the server itself stop responding/booting/etc., or did the OS stop booting, giving errors, etc.
Poweredge t110 ii server . i received the server without the battery , yesterday the electricity stopped for along of time and the system failed to open or boot the previous installed Ubuntu( with raid 5) . i want to know if there is a relation between the missing battery and the system fall . If there is no relation could you please tell me other things that may cause system fall ?? (NOTE : we are using UPS last for 30 minutes) i also want to know a solution to reset the RAID to the default configuration because when i tried to re-install Ubuntu the installation failed to see the other 3 hard disks and show only one !! Thanks in advance
Battery missing