Re: SSD + RAID

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.