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Date: Sun, 02 Oct 2011 18:44:21 -0600
From: David Boreham <david_list@boreham.org>
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To: "pgsql-performance@postgresql.org" <pgsql-performance@postgresql.org>
Subject: Re: Suggestions for Intel 710 SSD test
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On 10/2/2011 6:26 PM, Gregory Gerard wrote:
> If I may ask what were your top three candidates before choosing the intel?
All the other options considered viable were using traditional 
rotational disks.
I personally don't have any confidence in the other SSD vendors today,
except perhaps for FusionIO (where a couple of old friends work, and I 
can certainly vouch for
their competence) but their products are too costly for our application 
at present.
>
> Also why not just plan a graceful switch to a replicated server? At some point you have to detect the drive is about to go (or it just goes without warning). Presumably that point will be in a while and be coordinated with an upgrade like 9.2 in a year.
Sure, we have this capability but once you walk through what has to 
happen if you are burning through
SSDs every few months, the 710 value proposition is more attractive for 
us. For example our data center
is 1200 miles from our HQ and it takes a very long road trip or a plane 
flight to get hands-on with the
boxes. We spent some considerable time planning for the 320 style 
deployment to be honest --
figuring out how to predict when the drive would wear out, building 
replication mechanisms that
would cope gracefully and so on. But given the option of the 710 where 
wear out can essentially
be crossed off the list of things to worry about, that's the way we 
decided to go.
>
> Finally why not the pci based cards?
>
Few reasons: 1) Today Intel doesn't make them (that will change soon),
2) a desire to maintain backwards compatibility at least for this 
generation, on a system architecture level
with traditional disk drives, 3) concerns about mechanical integrity and 
system airflow issues with the
PCI card and connector in 1U enclosures. The SSD fits into the same 
location as a traditional disk
but can be velcro'ed down rather than bolted for easier field replacement.