[CentOS] Gracefully powering off system in case of power failure

Sat Jul 4 08:39:46 UTC 2015
Peter <peter at pajamian.dhs.org>

On 07/04/2015 08:32 PM, Jatin Davey wrote:
>> I've never heard of a UPS built into a server,
> No , i was referring to the battery backup unit within the server.

This sounds like it might actually be a battery backup unit (BBU) for
the RAID card in the server.  This is common but different to a UPS.
What the BBU does is backup the volatile RAM for the RAID write cache so
you don't end up corrupting your RAID in the event of a power failure
during a write, the write can then be completed from the cache once
power is restored.  This cannot be used to keep the server running for
any length of time or gracefully shutdown the server in the event of a
power failure, it simply protects the write cache on your RAID.