Subject: Re: Capacitors, etc., in hard drives and SSD for DBMS
 machines...
To: pgsql-performance@postgresql.org
References: <577F7F2A.10307@verizon.net>
From: Karl Denninger <karl@denninger.net>
Message-ID: <31c32f1d-2c36-a8da-1653-43273fd86d65@denninger.net>
Date: Fri, 8 Jul 2016 08:27:37 -0500
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On 7/8/2016 05:23, Jean-David Beyer wrote:
> Why all this concern about how long a disk (or SSD) drive can stay up
> after a power failure?
Never had a power supply fail, have you?  Or (accidentally) pull the
wrong cord? :)
> It seems to me that anyone interested in maintaining an important
> database would have suitable backup power on their entire systems,
> including the disk drives, so they could coast over any power loss.
>
> I do not have any database that important, but my machine has an APC
> Smart-UPS that has 2 1/2 hours of backup time with relatively new
> batteries in it. It is so oversize because my previous computer used
> much more power than this one does. And if my power company has a brown=

> out or black out of over 7 seconds, my natural gas fueled backup
> generator picks up the load very quickly.
>
> Am I overlooking something?
Yep -- Murphy.  And he's a bastard.

--=20
Karl Denninger
karl@denninger.net <mailto:karl@denninger.net>
/The Market Ticker/
/[S/MIME encrypted email preferred]/

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pe">
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    On 7/8/2016 05:23, Jean-David Beyer wrote:<br>
    <blockquote cite=3D"mid:577F7F2A.10307@verizon.net" type=3D"cite">
      <pre wrap=3D"">Why all this concern about how long a disk (or SSD) =
drive can stay up
after a power failure?</pre>
    </blockquote>
    Never had a power supply fail, have you?=C2=A0 Or (accidentally) pull=
 the
    wrong cord? :)
    <blockquote cite=3D"mid:577F7F2A.10307@verizon.net" type=3D"cite">
      <pre wrap=3D"">It seems to me that anyone interested in maintaining=
 an important
database would have suitable backup power on their entire systems,
including the disk drives, so they could coast over any power loss.

I do not have any database that important, but my machine has an APC
Smart-UPS that has 2 1/2 hours of backup time with relatively new
batteries in it. It is so oversize because my previous computer used
much more power than this one does. And if my power company has a brown
out or black out of over 7 seconds, my natural gas fueled backup
generator picks up the load very quickly.

Am I overlooking something?
</pre>
    </blockquote>
    Yep -- Murphy.=C2=A0 And he's a bastard.
    <br>
    <br>
    <div class=3D"moz-signature">-- <br>
      Karl Denninger<br>
      <a href=3D"mailto:karl@denninger.net">karl@denninger.net</a><br>
      <i>The Market Ticker</i><br>
      <font size=3D"-2"><i>[S/MIME encrypted email preferred]</i></font>
    </div>
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