From: Scott Marlowe <scott.marlowe@gmail.com>
To: Greg Smith <greg@2ndquadrant.com>
Cc: Mark Mielke <mark@mark.mielke.cc>
Cc: Arjen van der Meijden <acmmailing@tweakers.net>
Cc: pgsql-performance@postgresql.org
Subject: Re: SSD + RAID
Date: Mon, 22 Feb 2010 19:21:40 -0700
Message-ID: <dcc563d11002221821p773906a5hf3d3ffaf39bbddc6@mail.gmail.com> (raw)
In-Reply-To: <4B8331D5.7000802@2ndquadrant.com>
References: <201002211410.o1LEAht05941@momjian.us>
<4B814920.1040204@cheapcomplexdevices.com>
<4B82187A.7060604@2ndquadrant.com>
<4B822DFF.50501@tweakers.net>
<4B8329A3.4040003@2ndquadrant.com>
<4B832B3E.9080207@mark.mielke.cc>
<4B8331D5.7000802@2ndquadrant.com>
On Mon, Feb 22, 2010 at 6:39 PM, Greg Smith <greg@2ndquadrant.com> wrote:
> Mark Mielke wrote:
>>
>> I had read the above when posted, and then looked up SRAM. SRAM seems to
>> suggest it will hold the data even after power loss, but only for a period
>> of time. As long as power can restore within a few minutes, it seemed like
>> this would be ok?
>
> The normal type of RAM everyone uses is DRAM, which requires constrant
> "refresh" cycles to keep it working and is pretty power hungry as a result.
> Power gone, data gone an instant later.
Actually, oddly enough, per bit stored dram is much lower power usage
than sram, because it only has something like 2 transistors per bit,
while sram needs something like 4 or 5 (it's been a couple decades
since I took the classes on each). Even with the constant refresh,
dram has a lower power draw than sram.
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To: pgsql-performance@postgresql.org
Cc: scott.marlowe@gmail.com, greg@2ndquadrant.com, mark@mark.mielke.cc, acmmailing@tweakers.net
Subject: Re: SSD + RAID
In-Reply-To: <dcc563d11002221821p773906a5hf3d3ffaf39bbddc6@mail.gmail.com>
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