pg.ddx.io  pgsql-performance@postgresql.org mailing list archive  

help / color / mirror / Atom feed
From: Evgeny Shishkin <itparanoia@gmail.com>
To: David Boreham <david_list@boreham.org>
Cc: pgsql-performance@postgresql.org
Subject: Re: Do I have a hardware or a software problem?
Date: Wed, 12 Dec 2012 07:11:43 +0400
Message-ID: <24A86283-CED5-45A1-B60F-3CEEF4A3DFDB@gmail.com> (raw)
In-Reply-To: <50C7F469.7010301@boreham.org>
References: <AE27BD07-7A3A-449A-BD3F-A0DF4EF76C04@autouncle.com>
	<8F7661E7-D6D4-4334-8C6A-A8B6C56A2C3F@autouncle.com>
	<50C7351C.30407@2ndQuadrant.com>
	<4507A68A-3CD5-4283-AFA5-1C0593427E14@autouncle.com>
	<67FBF3AF-5C6A-45D4-9206-7257C8C01C5E@gmail.com>
	<CADZnK0nmm=2WnVVsveu3j0sJ95Ct13SqKbjQ_9DeVCGAmrcggw@mail.gmail.com>
	<E2A43856-FE0A-44BC-9764-C3CA533D94D9@gmail.com>
	<CADZnK0=0q9Ti9jVpCX3VX=3X_Rs=AxONhxC9cejnbOd5GKjb4A@mail.gmail.com>
	<ED7DEE06-B822-43E0-AF49-D89BB40C4C83@gmail.com>
	<50C7D7D2.4070605@2ndQuadrant.com>
	<2BCB6843-1396-42C9-A5BF-21C7C978FF4B@gmail.com>
	<50C7DDDE.1000000@2ndQuadrant.com>
	<3ADBD9A3-966F-40E8-AF78-0F2093D79BEE@gmail.com>
	<50C7E598.2070902@2ndQuadrant.com>
	<8A08ED7E-CF78-4F40-ACF1-1C87CEBBD00A@gmail.com>
	<50C7E8C5.9050300@boreham.org>
	<0D2E3F80-D94B-43DA-88E3-DA036FEA2241@gmail.com>
	<50C7EB65.8020806@boreham.org>
	<9E881CED-55D2-4E38-A1A6-CBCC47335B34@gmail.com>
	<50C7EEC3.8040202@boreham.org>
	<E918348F-82AA-4AEE-B13D-EB006DF1EFAB@gmail.com>
	<50C7F469.7010301@boreham.org>
List-Unsubscribe:  <mailto:majordomo@postgresql.org?body=unsub%20pgsql-performance>


On Dec 12, 2012, at 7:05 AM, David Boreham <david_list@boreham.org> wrote:

> On 12/11/2012 7:49 PM, Evgeny Shishkin wrote:
>> Yeah, s3700 looks promising, but sata interface is limiting factor for this drive.
>> I'm looking towards SMART ssd http://www.storagereview.com/smart_storage_systems_optimus_sas_enterprise_ssd_review
>> 
> What don't you like about SATA ?
> 
> I prefer to avoid SAS drives if possible due to the price premium for dubious benefits besides vague hand-waving "enterprise-ness" promises.
> 

Quoting http://www.storagereview.com/intel_ssd_dc_s3700_series_enterprise_ssd_review

Intel makes the case that the S3700 is the ideal drive for entry, mainstream and performance enterprise computing including HPC use cases. The claim is bold, largely because of the decision to go with a SATA interface, which has several limitations in the enterprise. The SATA interface tops out at a queue depth 32 (SAS scales as high as 256 in most cases) which means that when requests go above that level average and peak latency spike as we saw in all of our workloads.

Another huge advantage of SAS is the ability to offer dual-port modes for high availability scenarios, where there are two controllers interfacing with the same drive at the same time. In the event one goes offline, the connection with the SSD is not lost, as it would with a standard SATA interface without additional hardware. Some SAS drives also offer wide-port configurations used to increase total bandwidth above a single-link connection. While the Intel SSD DC S3700 against other SATA competitors is very fast, the story changes when you introduce the latest MLC and SLC-based SAS SSDs, which can cope better with increased thread and queue levels.

We picked the primary post-preconditioning sections of our benchmarks after each SSD had reached steady-state. For the purposes of this section, we added the Intel SSD DC S3700 onto the throughput charts of the newest SAS high-performance SSDs. There are also significant latency differences at higher queue depths that play a significant factor, but for the sake of easy comparison we stick with raw I/O speed across varying thread and queue counts.

In a 100% 4K random write or random read scenario, the Intel SSD DC 3700 performs quite well up against the high-end SAS competition, with the second fastest 4K steady-state speed. When you switch focus to read throughput at a heavy 16T/16Q load it only offers 1/2 to 1/3 the performance of SSDs in this category.

http://www.storagereview.com/images/intel_ssd_dc_s3700_main_slc_4kwrite_throughput.png


> 
> 
> 
> -- 
> Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org)
> To make changes to your subscription:
> http://www.postgresql.org/mailpref/pgsql-performance

view thread (35+ messages)  latest in thread

Message-ID: <24A86283-CED5-45A1-B60F-3CEEF4A3DFDB@gmail.com>
Permalink:  ../24A86283-CED5-45A1-B60F-3CEEF4A3DFDB@gmail.com/
Also on:    postgresql.org/message-id/24A86283-CED5-45A1-B60F-3CEEF4A3DFDB@gmail.com

 · 

reply
Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: pgsql-performance@postgresql.org
  Cc: itparanoia@gmail.com, david_list@boreham.org
  Subject: Re: Do I have a hardware or a software problem?
  In-Reply-To: <24A86283-CED5-45A1-B60F-3CEEF4A3DFDB@gmail.com>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox