From: David Boreham <david_list@boreham.org>
To: pgsql-performance@postgresql.org
Subject: Re: New server setup
Date: Wed, 13 Mar 2013 14:16:16 -0600
Message-ID: <5140DE90.5010009@boreham.org> (raw)
In-Reply-To: <5140D226.4060609@pinpointresearch.com>
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On 3/13/2013 1:23 PM, Steve Crawford wrote:
>
> What concerns me more than wear is this:
>
> InfoWorld Article:
> http://www.infoworld.com/t/solid-state-drives/test-your-ssds-or-risk-massive-data-loss-researchers-w...
>
>
> Referenced research paper:
> https://www.usenix.org/conference/fast13/understanding-robustness-ssds-under-power-fault
>
>
> Kind of messes with the "D" in ACID.
It is somewhat surprising to discover that many SSD products are not
durable under sudden power loss (what where they thinking!?, and ...why
doesn't anyone care??).
However, there is a set of SSD types known to be designed to address
power loss events that have been tested by contributors to this list.
Use only those devices and you won't see this problem. SSDs do have a
wear-out mechanism but wear can be monitored and devices replaced in
advance of failure. In practice longevity is such that most machines
will be in the dumpster long before the SSD wears out. We've had
machines running with several hundred wps constantly for 18 months using
Intel 710 drives and the wear level SMART value is still zero.
In addition, like any electronics module (CPU, memory, NIC), an SSD can
fail so you do need to arrange for valuable data to be replicated.
As with old school disk drives, firmware bugs are a concern so you might
want to consider what would happen if all the drives of a particular
type all decided to quit working at the same second in time (I've only
seen this happen myself with magnetic drives, but in theory it could
happen with SSD).
--
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To: pgsql-performance@postgresql.org
Cc: david_list@boreham.org
Subject: Re: New server setup
In-Reply-To: <5140DE90.5010009@boreham.org>
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