Re: SSD selection - Mailing list pgsql-performance

From Merlin Moncure
Subject Re: SSD selection
Date
Msg-id CAHyXU0y6yrDL6NwBEC_DLDEQoqsyfj8i-p2iOP71--vSzZpZTg@mail.gmail.com
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In response to Re: SSD selection  (David Boreham <david_list@boreham.org>)
Responses Re: SSD selection  (David Boreham <david_list@boreham.org>)
Re: SSD selection  (Greg Smith <greg@2ndQuadrant.com>)
List pgsql-performance
On Tue, May 15, 2012 at 3:00 PM, David Boreham <david_list@boreham.org> wrote:
> On 5/15/2012 12:16 PM, Rosser Schwarz wrote:
>>
>> As the other posters in this thread have said, your best bet is
>> probably the Intel 710 series drives, though I'd still expect some
>> 320-series drives in a RAID configuration to still be pretty
>> stupendously fast.
>
> One thing to mention is that the 710 are not faster than 320 series (unless
> in your definition of fast you count potential GC pauses of course).
> The 710's primary claim to fame is that it has endurance and GC
> characteristics designed for server and database use (constant load, heavy
> write load).
>
> So 320 drives will be just as fast, if not faster, but they will wear out
> much more quickly (possibly not a concern for the OP in his deployment) and
> may suffer from unwelcome GC pauses.

Although your assertion 100% supported by intel's marketing numbers,
there are some contradicting numbers out there that show the drives
offering pretty similar performance.  For example, look here:
http://www.anandtech.com/show/4902/intel-ssd-710-200gb-review/4 and
you can see that 4k aligned writes are giving quite similar results
(14k iops) even though the 710 is only rated for 2700 iops while the
320 is rated for 21000 IOPS.  Other benchmarks also show similar
results.

???

I have a theory that Intel rates their drives for IOPS based on the
results of 'Wheel of Fortune'.  This will be confirmed when you start
seeing drives with ratings of 'Bankrupt', 'Trip to Las Vegas', etc.
These must be the same guys that came up with the technical
explanation for the write through caching for the X25-M.

merlin

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