Message-ID: <4E555444.1090601@boreham.org>
Date: Wed, 24 Aug 2011 13:43:00 -0600
From: David Boreham <david_list@boreham.org>
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64;
	rv:6.0) Gecko/20110812 Thunderbird/6.0
MIME-Version: 1.0
To: pgsql-performance@postgresql.org
Subject: Re: Reports from SSD purgatory
References: <4E49B0A0.2060705@2ndQuadrant.com>
	<201108241848.061232@ms14.lnh.mail.rcn.net>
	<d32d411b09d8e7c614772de567a94229.squirrel@sq.gransy.com>
In-Reply-To: <d32d411b09d8e7c614772de567a94229.squirrel@sq.gransy.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit

On 8/24/2011 1:32 PM, Tomas Vondra wrote:
> Why is that important? It's simply a failure of electronics and it has 
> nothing to do with the wear limits. It simply fails without prior 
> warning from the SMART.

In the cited article (actually in all articles I've read on this 
subject), the failures were not properly analyzed*.
Therefore the conclusion that the failures were of electronics 
components is invalid.
In the most recent article, people have pointed to it as confirming 
electronics failures
but the article actually states that the majority of failures were 
suspected to be
firmware-related.

We know that a) there have been failures, but b) not the cause.

We don't even know for sure that the cause was not cell wear.
That's because all we know is that the drives did not report
wear before failing. The wear reporting mechanism could be broken for 
all we know.

--
*A "proper" analysis would involve either the original manufacturer's FA 
lab, or a qualified independent analysis lab.