[rescue] little low-wattage servers

J. Alexander Jacocks jjacocks at mac.com
Mon Feb 6 14:21:29 CST 2012

On Mon, Feb 6, 2012 at 2:43 PM, Mouse <mouse at rodents-montreal.org> wrote:

> > Also, how many folks are using hardware raid, at all, these days?  I
> > discovered several years ago that properly configured software RAID
> > is much faster, and quite often easier to manage, than hardware RAID.
> ...when it's applicable.
> > Even without ZFS, LVM on top of MD raid (on Linux, or course),
> Not everyone runs Linux, "of course" or not.  Nor should.
> > Only caveat being that you can't boot from RAID-5+,
> That's another plausible reason.
> Firmware (or, occasionally, hardware) RAID has the property (at least
> when done right - anything can be done wrong) that it requires no
> support whatever from the software running on the host.  You can boot
> from it, you can run specialized software that's never _heard_ of
> software RAID, and it all Just Works.  It also doesn't soak up host CPU
> cycles.  In some cases these properties are advantages.
> Software RAID has the property (ditto) that it requires no support from
> the hardware.  The disk, the machine, don't have to - and, in a sense,
> cannot - know RAID is going on.  This makes for transportability and
> easy bugfixes.  In some cases these properties are advantages.
> And, of course, each one has its costs.  But to speak of the advantages
> of either as though everyone shared them, or should share them,
> is...misleading, at best.

I wasn't implying that everyone runs Linux, at all.  More just the fact
that when I see Solaris, these days, I generally see ZFS (RAID-Z).  When I
see FreeBSD, I see RAIDframe.  The point I was making is that the cost of a
RAID controller is generally not worth the investment, today, when software
RAID is more flexible, and generally either free, or included in the price
of the OS.

In the old days of having to purchase a VxVM (hp-ux/Solaris), or a
RAID-feature (DIGITAL UNIX/Tru64) license, hardware RAID was often
cheaper.  And, we didn't use to have the glut of unused CPU cycles that
most modern hardware provide.  So, hardware RAID controllers definitely
made sense.

That was my whole argument.  Is that more clear?

- Alex

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