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Date: Wed, 1 Apr 2009 11:58:49 -0600
Message-ID: <dcc563d10904011058m38324c9ei69d77ea7a9eef6ec@mail.gmail.com>
Subject: Re: Raid 10 chunksize
From: Scott Marlowe <scott.marlowe@gmail.com>
To: Matthew Wakeling <matthew@flymine.org>
Cc: "pgsql-performance@postgresql.org" <pgsql-performance@postgresql.org>
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On Wed, Apr 1, 2009 at 11:54 AM, Matthew Wakeling <matthew@flymine.org> wro=
te:
> On Wed, 1 Apr 2009, Greg Smith wrote:
>>
>> The only real way to know if a UPS is working right is to actually detac=
h
>> power and confirm the battery still works, which is downtime nobody ever
>> feels is warranted for a production system. =A0Then, one day the power d=
ies,
>> the UPS battery doesn't work to spec anymore, and you're done.
>
> Most decent servers have dual power supplies, and they should really be
> connected to two independent UPS units. You can test them one by one with=
out
> much risk of bringing down your server.

Yeah, our primary DB servers have three PSes and can run on any two
just fine.  We have three power busses each coming from a different
UPS at the hosting center.