[H-GEN] U.P.S

David Jericho david.jericho at bytecomm.com.au
Mon Sep 16 19:26:28 EDT 2002


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On Tue, Sep 17, 2002 at 08:15:11AM +1000, Hog Snort Rupert wrote:
> A test with just one boxen attached [no monitor] showed that the E Smith
> router/firewall would run for +/- 10 minutes, after the UPS was unplugged from
> the wall.
> I guess that a pair of new batteries would see it run for a little/lot longer.
> But I don't know what the "norm" for these things.

It varies on your load of course, but one PC with a basic UPS with two
normal batteries, I'd be guessing at _least_ half an hour with a medium 
sized monitor. More like an hour is what I'd consider useful.

One thing to keep in mind with UPS units is that many of the lesser
models don't prevent overvoltage or spikes, they only accomodate for 
under voltage. Spending a few bucks on surge protector _between_ the 
UPS and your PC equipment is worth it.

You don't want to place it between the UPS and the wall, because some
cheaper UPS equipment can causes surges themselves.

As a side note of interest, my employer won the former Brisbane
exchange One.Tel UPS, for a disgustingly low price (think 3 digits).

6 tonnes, 72 2v 3840 Ah @ 8 hours batteries, and a very satisfyingly
large On/Off switch. The switch being the most important factor.

> What software is needed by Linux? I thought this thing was just hardware.
> A sort of "Plug in 'n leave alone".

Well, they can be, but the neat factor of UPS units is that they can
tell you when they've had enough, and cause a clean shutdown that
doesn't risk data corruption.

Not a big deal for one PC, but when you've got 8 racks cram packed
full of gear ranging from web servers to Oracle boxen, and inhouse
file servers, it's quite a headache to go around and manually force a
filesystem check on each machine.

-- 
David Jericho
Senior Systems Administrator, Bytecomm Pty Ltd

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