adding BBU relearn support to mfiutil

[Mark Johnston]

On Fri, Apr 05, 2013 at 02:22:36PM -0700, Sean Bruno wrote:
> On Sun, 2013-03-03 at 22:38 -0500, Mark Johnston wrote:
> > Hi Everyone,
> > 
> > I recently needed to add a couple of features to mfiutil related to BBU
> > relearning. I've pasted a patch below which
> > 
> > 1. adds extra fields to the output of "mfiutil show battery" showing BBU
> >    properties. This is essentially the output of
> > 
> >    # MegaCli -AdpBbuInfo -GetBbuProperties -aLL
> > 
> >    and consists of info about battery learning: the learn period, the
> >    time at which the controller will start the next relearn, and the BBU
> >    mode (which indicates whether the battery supports transparent
> >    relearning).
> > 
> > 2. adds a couple of subcommands under "mfiutil bbu" which lets users set
> >    the BBU properties which can be set by MegaCli.
> > 
> > 3. adds a command "mfiutil start learn" which immediately kicks off a
> >    battery relearn.
> > 
> > These changes grew out of concern about the fact that the controller
> > write cache is set to write-through mode during a relearn period (which
> > usually lasts for several hours). This ended up causing some mysterious
> > and intermittent performance issues, so I needed a way of getting more
> > info about what was going on (using MegaCli isn't really an option for
> > several reasons). Some BBUs support transparent relearning, which
> > basically means that the controller write cache doesn't get turned off
> > during a relearn. However, LSI's default config doesn't enable it, and
> > now mfiutil can be used to do that (through "mfiutil bbu bbu-mode").
> > 
> > I was hoping someone would be able to review the patch. If anyone's able
> > and willing to test it, I'd very much appreciate feedback from that.
> > 
> > Thanks!
> > -Mark
> 
> Just to document for the record.  Finally got around to testing this
> today with Mark providing updates.  Looks good overall with a couple of
> nits that he is handling at the moment (man page and variable name
> collision).

The updated patch is here:
http://people.freebsd.org/~markj/patches/20130405-mfi-bbu.diff

I'll commit it in a few days if there aren't any problems.

Thanks,
-Mark