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[ale] OT: U.P.S. Recommendations

Some of the previous posters make good points about very sensitive
equipment and generators.  (I have yet to try driving my UPSs from
my fairly new generator.)

That said, I've used exclusively APC for about 12 years with excellent
success.  That includes NO fried equipment even though one of my ceiling
fans fried during a storm.  Standard boxes, even cheap white boxes,
will do just fine with APC or others that only invert when the Georgia
Power doesn't.


1. You need to change your UPS batteries every 3-5 years.  To test
   their health shut your systems down and boot to the BIOS level
   and leave them there.  That means that you will NOT have active
   file systems that could get corrupted on abrupt shut down.

   Pull the UPS's power cord from the wall and start timing (disable
   any automatic system shutdown if needed).

   See how long the system gets power before the UPS battery fails.
   If your system's disk normally tends to be active deduct 10-30%
   from the up time or do so anyway for margin.

   If this time is too short either buy a new batter at Batteries Plus
   (Duluth or Marietta) or buy a new UPS.

   This really is the only reliable way to measure running time.
   NOTE that the rated power on a system's data plate is the maximum
   power except surges.  Typically, a system normally uses only
   30-50% of that power, according to my AC Ammeter.

2. Convert all of your systems to use a journaling file system such
   as ext3 or Reiser.  Thus, if the system does lose power there is
   only a very small chance of file system corruption.

3. Remove your laptops (unless their internal batteries are dead) from
   the UPS and connect instead to the surge protector outlets.

4. Ensure that phone lines or cable lines coming into your modems
   first go through a surge protector.  Some APC surge protectors
   offer a connection for cable and it has worked fine for me since

5. Analyze your rat's nest of wires.  Make sure that wires outside of
   UPS-protected circuits are at least a foot from wires that are
   inside protected circuits.  This is to reduce the chance of a direct
   hit causing an spark around the UPS.  Many people forget this step.

6. If you have long runs of Ethernet cable, consider having each end
   go through a surge protector to protect against induced surges.
   One friend got fried equipment by forgetting this.

7. Do frequent off-site backups in case your equipment gets fried anyway.

Bob Toxen
bob at verysecurelinux.com               [Please use for email to me]
http://www.verysecurelinux.com        [Network&Linux/Unix security consulting]
http://www.realworldlinuxsecurity.com [My book:"Real World Linux Security 2/e"]
Quality Linux & UNIX security and SysAdmin & software consulting since 1990.

"Microsoft: Unsafe at any clock speed!"
   -- Bob Toxen 10/03/2002

On Wed, Apr 11, 2007 at 09:32:32PM -0400, aaron wrote:
> I've been trusting the life of my computers to the Southern
> Company monopolists and Georgia Power for as long as I've
> I've been living with computers (or, in their little silicon minds,
> living _for_ them).

> In truth, the electricity has been generally reliable and consistent
> in my area, at least as far as I can tell without having ever put
> meters on it, but I'm overdue to start playing a little safer and
> invest in a U.P.S. / Power conditioning system to help safeguard
> my money machines.

> I'm looking to provide power to a couple 400 watt computers with
> CRT monitors plus a few external disk drives. A 30 minute battery
> run time would ride through most of the occasional bumps and brief
> outages that happen here. Don't need any remote monitoring or
> alerts and such since these aren't server systems.  Just looking for
> advice on appropriate size and brands that are a reliable value.

> Like any computerized rubbish bin would say...
>      Any Input Appreciated!

> peace
> aaron