From: John Lister <john.lister@kickstone.com>
To: Steve Crawford <scrawford@pinpointresearch.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: New server setup
Date: Wed, 13 Mar 2013 20:05:52 +0000
Message-ID: <5140DC20.60306@kickstone.com> (raw)
In-Reply-To: <5140D226.4060609@pinpointresearch.com>
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On 13/03/2013 19:23, Steve Crawford wrote:
> On 03/13/2013 09:15 AM, John Lister wrote:
>> On 13/03/2013 15:50, Greg Jaskiewicz wrote:
>>> SSDs have much shorter life then spinning drives, so what do you do
>>> when one inevitably fails in your system ?
>> Define much shorter? I accept they have a limited no of writes, but
>> that depends on load. You can actively monitor the drives "health"
>> level...
>
> 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...
>
When I read this they didn't name the drives that failed - or those that
passed. But I'm assuming the failed ones are standard consumer SSDS, but
2 good ones were either enterprise of had caps. The reason I say this,
is that yes SSD drives by the nature of their operation cache/store
information in ram while they write it to the flash and to handle the
mappings, etc of real to virtual sectors and if they loose power it is
this that is lost, causing at best corruption if not complete loss of
the drive. Enterprise drives (and some consumer, such as the 320s) have
either capacitors or battery backup to allows the drive to safely
shutdown. There have been various reports both on this list and
elsewhere showing that these drives successfully survive repeated power
failures.
A bigger concern is the state of the firmware in these drives which
until recently was more likely to trash your drive - fortunately things
seems to becoming more stable with age now.
John
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To: pgsql-performance@postgresql.org
Cc: john.lister@kickstone.com, scrawford@pinpointresearch.com
Subject: Re: New server setup
In-Reply-To: <5140DC20.60306@kickstone.com>
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