[Nut-upsdev] Asking hard questions about the NUT architecture

[Rob MacGregor]

On 5/29/07, Eric S. Raymond <esr at thyrsus.com> wrote:
>
> 1. In an era when file systems are normally journaled and hardened so they
> recover clean from power failures, what point is there in having your UPS
> initiate a controlled shutdown N seconds beforehand?

Somebody else has already raised the clean application shutdown, so I
won't repeat that.

However, back in the human world, why shouldn't the admin know that
the power has gone out and the system is now on battery support?
Getting the page to say that it's all going wrong *before* the lights
go out can be rather useful :)

> 2. Why should we care about contact-closure UPSes any more?
<---SNIP--->
> It follows that NUT could drop all support for contact-closure and
> "dumb" UPSes tomorrow and it wouldn't make a damn bit of difference
> to anybody, at least nobody in the Linux world.  Ext3 is everywhere
> now, and the odds that Linux distros will drop back to a non-hardened
> filesystem in the future are nil.

But there's more than just Linux out there (and, while ext3 is better
than ext2, I've still personally experienced edge cases where those
multi TB file systems require a full fsck, which is time consuming and
painful).

> 3.  Why should we care about 'smart' serial UPSes any more?
>
> I've already shown that supporting dumb UPSes is silly under modern
> conditions.  Supporting anything RS232, in particular smart serial
> UPSes, seems almost as pointless in 2007.  USB UPSes are ubiquitous
> and cheap; when I recently went shopping for a UPS I found a
> USB-capable unit for $29.99.  Belkin no longer manufactures any
> RS232-only units at all and APC hasn't shipped a new RS232-only design
> since at least 2004.

But why should I (or where I work) have to buy a new UPS when the old
one works just fine?

> I don't understand this objection, sorry.  What could NUT's UPS-controlled
> shutdown possibly be doing for you that a shutdown on SIGPWR wouldn't?

That'll be that Linux centric view again - FreeBSD doesn't support
SIGPWR (and, if I'm honest, it's USB support is still relatively
immature comparted to Linux), but it works just fine as a NUT master.

-- 
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Rob MacGregor
      Whoever fights monsters should see to it that in the process he
        doesn't become a monster.                  Friedrich Nietzsche