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Date: Mon, 28 Sep 2009 14:49:47 +0700 (ICT)
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From: Olivier Nicole <Olivier.Nicole@cs.ait.ac.th>
To: miklosovic.freebsd@gmail.com
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	(message from Stefan Miklosovic on Mon, 28 Sep 2009 09:40:31 +0200)
References: <f99a79ec0909280040y121864cfr58fac44df7e8dcca@mail.gmail.com>
Cc: freebsd-questions@freebsd.org
Subject: Re: battery reconditioning
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Hi,

> form time to time, there appears some error / warning
> messages in console, which say this:
> Sep 28 00:13:40 dell kernel: aac0: **Monitor** Battery needs reconditioning.

What is your question?

It informs you you should change the battery used on the RAID
hardware, so change the battery :)

Hardware RAID has a system to delay the write when the disk is
idled. The sectors to be written are kept in a temporary RAM and this
RAM is powered by batteries. When there is a power failure, the
battery should provide electricity to the hard disk, just long enough
to write back the sectors that have been delayed. If the battery
fails, these sectors will never be written.

So if the battery is bad, replace the battery.

Best 

Olivier