From: Greg Smith <greg@2ndQuadrant.com>
To: Jesper Krogh <jesper@krogh.cc>
Cc: pgsql-performance@postgresql.org <pgsql-performance@postgresql.org>
Subject: Re: Intel SSDs that may not suck
Date: Thu, 07 Apr 2011 01:48:26 -0400
Message-ID: <4D9D502A.2010600@2ndQuadrant.com> (raw)
In-Reply-To: <4D9D3D4D.300@krogh.cc>
References: <4D90EDB6.2080609@2ndQuadrant.com>
<4D9D3D4D.300@krogh.cc>
On 04/07/2011 12:27 AM, Jesper Krogh wrote:
> On 2011-03-28 22:21, Greg Smith wrote:
>> Some may still find these two cheap for enterprise use, given the use
>> of MLC limits how much activity these drives can handle. But it's
>> great to have a new option for lower budget system that can tolerate
>> some risk there.
>>
> Drifting of the topic slightly.. Has anyone opinions/experience with:
> http://www.ocztechnology.com/ocz-z-drive-r2-p88-pci-express-ssd.html
>
> They seem to be "like" the FusionIO drives just quite a lot cheaper,
> wonder what the state of those 512MB is in case of a power-loss.
What I do is assume that if the vendor doesn't say outright how the
cache is preserved, that means it isn't, and the card is garbage for
database use. That rule is rarely wrong. The available soon Z-Drive R3
includes a Sandforce controller and supercap for preserving writes:
http://hothardware.com/News/OCZ-Unveils-RevoDrive-X3-Vertex-3-and-Other-SSD-Goodness/
Since they're bragging about it there, the safe bet is that the older R2
unit had no such facility.
I note that the Z-Drive R2 is basically some flash packed on top of an
LSI 1068e controller, mapped as a RAID0 volume. It's possible they left
the battery-backup unit on that card exposed, so it may be possible to
do better with it. The way they just stack those card layers together,
the thing is practically held together with duct tape though. That's
not a confidence inspiring design to me. The R3 drives are much more
cleanly integrated.
--
Greg Smith 2ndQuadrant US greg@2ndQuadrant.com Baltimore, MD
PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.us
"PostgreSQL 9.0 High Performance": http://www.2ndQuadrant.com/books
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To: pgsql-performance@postgresql.org
Cc: greg@2ndQuadrant.com, jesper@krogh.cc
Subject: Re: Intel SSDs that may not suck
In-Reply-To: <4D9D502A.2010600@2ndQuadrant.com>
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