data loss after power failure

[shimi]

On Sat, Aug 15, 2009 at 7:26 AM, Amos Shapira <amos.shapira at gmail.com>wrote:

> 2009/8/14 Micha Silver <micha at arava.co.il>:
> > shimi wrote:
> >> Sample the UPS unit for "how much battery time left do you have?"  and
> >> initiate automatic shutdown when the number falls below the 5 minutes
> >> threshold ?
> >>
> > Yes, that's probably best. Thanks. The disadvantage is that after the
> power
> > comes back, someone has to physically go to power-up the servers.
>
> Well, that's how UPS's are supposed to be used.
>
> In addition to Wake-On-Lan mentioned by Shimi, there are also:
> 1. Boot on AC power - i.e. if the AC power comes back then start
> reboot. That's a BIOS setting.


Which assumes a power loss after the automatic shutdown. According to Murphy
law, and to my experience, power tends to return 1 minute before the battery
gets completely drained, just for me to wonder "why oh why did I shut down
my whole server room, it would have survived". Of course that if I wouldn't
have shut down everything, the outage would be 1 minute longer. :)

So still need WoL :) (to be initiated by the machine sampling for the UPS
remaining battery after the battery managed to re-charge for additional few
minutes of backup power - enough for a second power up and shutdown of
everything assuming a second outage...)

-- Shimi
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