Re: killed my computer


clare@xxxxxxxxxxxx wrote:

On Wed, 03 Dec 2008 09:09:08 -0600, "Pete C." <aux3.DOH.4@xxxxxxxx>
wrote:


jk wrote:

Larry Jaques <novalidaddress@di\/ersify.com> wrote:

You 'splain me, Tawmy? (No info was found online during a quick
googling for it.)

I've always had passives and they've worked fine. Who makes actives
and what's the price differential?

WHat he defines as an "active" UPS is more commonly referred to as a
"double conversion" ups.

In a double conversion UPS all of the power is converted to DC, to
feed the DC bus and charge the batteries. THe DC is then turned into
(via an inverter) AC that is completely separate from your AC line.
When your input goes away, you just continue , but start discharging
your battery.

THe other type of ups, feeds input power straight out to the load, and
also charges a battery. WHen it senses a power problem, it starts the
inverter and then uses a relay to swap the output to it. Not a big
deal if the problem is a slow rise or fall in the voltage. But a
surge, or a total outage,[or other high speed events] which travel at
effectively the speed of light, reach your power supply before the
relay can do any thing about them.

OTOH, they are MUCH cheaper.

[I have also had the fun of listening to them oscillate in a server
room. As they decided the power was OK again, they all [1 SUPS per
server] switched back at the same time [Factory default]. THis caused
enough of a sag [when the line voltage was a little low, while doing a
generator test]
that they all switched back to battery, but then the power was ok
again, so they all switch back to the line.....and so on and so on.]

jk

That last bit is why once a site is big enough to have a "server room"
of any consequence, the little individual UPSes need to go the way of
the dodo and be replaced by larger "real" UPSes. When you get big enough
you have multiple huge UPSes, battery rooms, static transfer switches,
etc. and "real" power management.

And somewhere in between a few good midsize dual conversions give you
the capacity for some redundancy. You ARE running redundant servers,
are you not???? What good are redundant servers if they are taken down
by the failure of une UPS??

We have 2 servers, one with redundant power supplies, one without -
with one UPS powering each power supply on the dual supply unit, while
the single power supply unit takes one UPS while the"maintenance"
workstation takes the other.

We have UPSes with battery rooms feeding three phase 480V static
transfer switches and PDUs, backed by big diesel generators with lots of
fuel. Nearly every piece of equipment has N+1 power supplies fed from
separate PDUs on separate UPSes. Redundant servers are in different
states.

At home I'm a little more lax with single UPSes in my office and on my
server rack in the garage, backed by two generators, one as primary
which I typically have online in 5 minutes and one as backup which can
be online a few minutes later if need be. Server rack UPS gets around
45min or better of battery run time.
.

Relevant Pages

  • Re: UPS waveform question for SUN servers
    ... O.K. The pure sine wave is better for systems with input ... The SB-1K and SB-2K use the same power supply. ... this UPS has caused more trouble than ... it has alleviated - with the battery sometimes discharging for no ...
    (comp.sys.sun.hardware)
  • Re: back-up power supply
    ... :I was thinking to get a back-up power supply for my PC and saw a book ... The least expensive type of UPS is 'passive'. ... the battery goes back out again when the power returns. ... One issue with passive UPSs is that the electricity is not flowing ...
    (comp.security.misc)
  • Re: ups installation question
    ... They protect connected devices from sudden power ... UPS AKA battery back-up: ... Most have surge protection et al, ... The issue of UPS vs. auto battery life is more a limitation of the ...
    (alt.sys.pc-clone.dell)
  • Re: Help! Hacker is turning off my server.
    ... ruin brand new batteries] and a minor power fluctuation would power the ... The UPS gave no indication of anything wrong. ... > Here are some other event logs that may give a hint to ... > The server was unable to add the virtual ...
    (microsoft.public.inetserver.iis.security)
  • Re: suggestions for a UPS
    ... If you use the Server Monitor application, ... (Power, System Poard, Estimated Input Power) ... for a while and note the average and peak power before selecting a UPS. ... it doesn't report the battery level, claiming to be at 100% capacity all ...
    (comp.sys.mac.system)