Re: Why database is corrupted after re-booting - Mailing list pgsql-general

Actually, because I lost several thousands of dollars or equipement a couple of
years ago, I recommended these "brickwall" products to a company.

http://brickwall.com/index.htm

We actually never deployed these units (grounding the communications lines ended
up being a much cheaper solution) but I did talk and engineer at the company and
apparently they have some hospitals as client that use unitss.  I'm won't get
into the technology of how they work since you can read that yourself but I
remember having a warm and fuzzy after my conversation.

I will pull one quote from their web site though...

"Unlike MOV’s, TRANS-ZORBS and similar shunt based surge protectors that use
elements weighing less than 1/4 ounce, Brick Wall surge protectors can easily
absorb any surge repeatedly with absolutely no degradation."

The important phrase here is "...absorb any surge repeatedly with absolutely no
degradation."

Quoting Tom Lane <tgl@sss.pgh.pa.us>:

> Alex Stapleton <alexs@advfn.com> writes:
> > suspicion is that if the power failure isn't a particularly fast one,
> > (e.g. you overloaded a fuse somewhere, fuses are insanely slow to
> > fail compared to alternatives like MCBs) then your RAID card's RAM
> > will get corrupted as the voltage drops or the system memory will
> > resulting in bad data getting copied to the RAID controller as RAM
> > seems to be pretty sensitive to voltage variations in experiments
> > i've done on my insanely tweak-able desktop at home. I would of
> > though ECC probably helps, but it can only correct so much.
>
> Any competently designed battery-backup scheme has no problem with this.
>
> What can seriously fry your equipment is a spike (ie, too much voltage
> not too little).  Most UPS-type equipment includes surge suppression
> hardware that offers a pretty good defense against this, but if you get
> a lightning strike directly where the power comes into your building,
> you're going to be having a chat with your insurance agent.  There is
> nothing made that will withstand a point-blank strike.
>
>             regards, tom lane
>
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--
Keith C. Perry, MS E.E.
Director of Networks & Applications
VCSN, Inc.
http://vcsn.com

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