From: Joshua D. Drake <jd@commandprompt.com>
To: Stefan Kaltenbrunner <stefan@kaltenbrunner.cc>
Cc: Gregory Stark <stark@enterprisedb.com>
Cc: Simon Riggs <simon@2ndquadrant.com>
Cc: Bernd Helmle <mailings@oopsware.de>
Cc: mfatticcioni@mbigroup.it
Cc: pgsql-performance@postgresql.org
Subject: Re: DRBD and Postgres: how to improve the perfomance?
Date: Sat, 08 Sep 2007 14:25:13 -0700
Message-ID: <46E31339.6090909@commandprompt.com> (raw)
In-Reply-To: <46E2DB04.1080803@kaltenbrunner.cc>
References: <2C070D1C3970467FF64F6B6A@imhotep.credativ.de>
<1189232904.4281.19.camel@ebony.site>
<87k5r1zd52.fsf@oxford.xeocode.com>
<46E2CAAF.50205@commandprompt.com>
<46E2CEF3.1030908@kaltenbrunner.cc>
<46E2D38A.6070607@commandprompt.com>
<46E2DB04.1080803@kaltenbrunner.cc>
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Stefan Kaltenbrunner wrote:
> Joshua D. Drake wrote:
>> Stefan Kaltenbrunner wrote:
>>> how is that making it different in practise ? - if both are on the same
>>> UPS they are affectively on the same power bus ...
>> Well I was thinking the bus that is in the wall. I would assume that
>> people were smart enough to have independent UPS systems for each server.
>>
>> city power->line conditioning generator->panel->plug->UPS->server
>>
>> wash, rinse repeat.
>
> the typical datacenter version of this is actually more like:
>
> city power->UPS (with generator in parallel)->panel->plug
Right, this is what we have at our colo except that I add a UPS where
appropriate in between panel and plug.
> city power->flywheel->(maybe UPS)->panel->plug
>
> it is not really that common to have say two different UPS feeds in your
> rack (at least not for normal housing or the average corporate
> datacenter) - mostly you get two feeds from different power distribution
> panels (so different breakers) but that's about it.
> Having a local UPS attached is usually not really that helpful either
> because those have limited capacity need space and are an additional
> thing that can (and will) fail.
We don't have the capacity issue. We use the UPS explicitly for specific
cases (like the one mentioned at the beginning of the thread). The whole
idea is to insure clean shutdown in case of "total" power failure.
Sincerely,
Joshua D. Drake
>
>
> Stefan
>
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To: pgsql-performance@postgresql.org
Cc: jd@commandprompt.com, stefan@kaltenbrunner.cc, stark@enterprisedb.com, simon@2ndquadrant.com, mailings@oopsware.de, mfatticcioni@mbigroup.it
Subject: Re: DRBD and Postgres: how to improve the perfomance?
In-Reply-To: <46E31339.6090909@commandprompt.com>
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