Message-ID: <519CE53C.1040703@2ndQuadrant.com>
Date: Wed, 22 May 2013 11:33:16 -0400
From: Greg Smith <greg@2ndQuadrant.com>
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To: Merlin Moncure <mmoncure@gmail.com>
CC: Tomas Vondra <tv@fuzzy.cz>, pgsql-performance@postgresql.org
Subject: Re: Reliability with RAID 10 SSD and Streaming Replication
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On 5/22/13 11:05 AM, Merlin Moncure wrote:
> unfortunately, I don't have a s3700 to
> test with, but based on everything i've seen it looks like it's a
> mostly solved problem. (for example, see here:
> http://www.storagereview.com/intel_ssd_dc_s3700_series_enterprise_ssd_review).
>    Tests that drive the 710 to <3k iops were not able to take the 3700
> down under 10k at any queue depth.

I have two weeks of real-world data from DC S3700 units in production 
and a pile of synthetic test results.  The S3700 drives are at least 2X 
as fast as the 710 models, and there are synthetic tests where it's 
closer to 10X.

On a 5,000 IOPS workload that crushed a pair of 710 units, the new 
drives are only hitting 50% utilization now.  Does that make worst-case 
10K?  Maybe.  I can't just extrapolate from the 50% figures and predict 
the throughput I'll see at 100% though, so I'm still waiting for more 
data before I feel comfortable saying exactly what the worst case looks 
like.

-- 
Greg Smith   2ndQuadrant US    greg@2ndQuadrant.com   Baltimore, MD
PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.com


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