Re: NT striping dangerous with Oracle 7 or 8?

In article <6djknn$uu$1_at_nnrp1.dejanews.com>, <bdurrett_at_ccci.org> wrote:
>I think you are right Steve. Our new building is supposed to have a UPS and a
>generator to backup up our system, so that would theoretically prevent the
>battery backup from running out. But if the power went out on a weekend and
>things didn't work with the generator we would still be toast when the battery
>backup ran out.

I worked in a place once that had just installed a huge UPS and Detroit Diesel generator. One day, the alarm on the ups went off. My boss kept resetting it, and it kept going off. Finally, he put a piece of tape over the alarm reset button. I had a feeling if the thing was complaining, something was wrong, so I went for a little walk, and saw the diesel was running. Turned out the thing had a swimming-pool style timer, set to turn the thing on once a week. But of course, no one set it to turn off, so both line voltage and generator voltage were being fed into the UPS. Unlike line voltage, the frequency of the generator voltage varied by several Hz, so no wonder the UPS was screaming... as two times 220V went in and out of phase...

>
>I checked into the post about disk drives write caching and I found out it was
>also true, but ours are set up with "write-through" type writing by default.
>So if we set our raid controller to write through we should be okay.
>
>We can still lose the data currently being written, but with database logging
>Oracle can recover it.
>
>- Bobby
>>
>> I sorta lost with the reasoning here, because you'd still be buggered when
>> the battery backup ran out... OK, you may have warning alarms, etc., but in
>> the middle of the night you might not be there to hear them.
>>
>> Surely a 'write through cache' is the only real solution?
>>
>> Steve Phelan.
>>
>> Eugen Nyffeler wrote in message <34FBDB7C.AE75B140_at_ubs.com>...
>> >bdurrett_at_ccci.org wrote:
>> ><snip>
>> >> Wow, so you are saying that you really can't protect your database from
>> >> losing data? If you lose writes to the redo log and to a data file
 wouldn't
>> >> you really be sunk? i.e. You couldn't even recover in that case. If you
 were
>> >> doing a lot of heavy updating and commiting transactions and the power
 went
>> >> out you could lose a bunch of stuff.
>> >>
>> >> But this is not NT specific I suppose. A Sun or HP unix box would have
 the
>> >> same issues, correct?
>> >
>> >Yeap,
>> >Any system which has no battery buffer will loos data which is only in
>> >the
>> >cache at this moment. Any system i know has this problem (Unix, NT,
>> >etc.).
>>
>>
>
>
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