Re: Why database is corrupted after re-booting

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