Received: from magus.postgresql.org (magus.postgresql.org [87.238.57.229])
	by mail.postgresql.org (Postfix) with ESMTP id BFE7CA684DE
	for <pgsql-performance@postgresql.org>;
	Mon, 21 May 2012 12:50:23 -0300 (ADT)
Received: from smtp.peak6.com ([38.98.137.6])
	by magus.postgresql.org with esmtp (Exim 4.72)
	(envelope-from <sthomas@optionshouse.com>) id 1SWUsF-0001H0-SV
	for pgsql-performance@postgresql.org; Mon, 21 May 2012 15:50:22 +0000
X-AuditID: 0a64cb1e-b7fb26d000001053-9b-4fba64212cf4
Message-ID: <4FBA642C.6040501@optionshouse.com>
Date: Mon, 21 May 2012 10:50:04 -0500
From: Shaun Thomas <sthomas@optionshouse.com>
Reply-To: <sthomas@optionshouse.com>
Organization: Peak6
User-Agent: Mozilla/5.0 (X11; Linux i686;
	rv:12.0) Gecko/20120430 Thunderbird/12.0.1
MIME-Version: 1.0
To: Scott Marlowe <scott.marlowe@gmail.com>
CC: Jan Nielsen <jan.sture.nielsen@gmail.com>,
	<pgsql-performance@postgresql.org>
Subject: Re: local-storage versus SAN sequential read performance
 comparison
References: 
 <CANxH4hHF8_qjiSoM5U_epPcRa2bu9N-wU8dArJOCQybYUxSV7w@mail.gmail.com>
	<CAOR=d=2NYpmrsJX=3-bWoPKGwzzaA=iZoqh=SCXu=GSGAzmiVA@mail.gmail.com>
In-Reply-To: 
 <CAOR=d=2NYpmrsJX=3-bWoPKGwzzaA=iZoqh=SCXu=GSGAzmiVA@mail.gmail.com>
Content-Type: text/plain; charset="ISO-8859-1"; format=flowed
content-transfer-encoding: 7bit
X-Originating-IP: [10.10.201.64]
X-Brightmail-Tracker: 
 H4sIAAAAAAAAA+NgFnrKIsWRmVeSWpSXmKPExsXClcIrpquYssvfoH+bgkXvpwlsFtdnnmO2
	WPbpPKMDs8fOWXfZPS7sm8YewBTVwGiTmJeXX5JYkqqQklqcbKvkX1CSmZ9X7JFfWpyq4JJZ
	nJyTmJmbWqSkkJliq2SupFCQk5icmpuaV2KrlFhQkJqXomTHpYABbIDKMvMUUvOS81My89Jt
	lTyD/XUtLEwtdQ2V7OKRQUInS8bkLadYC3pZKl6u/8HcwDifuYuRk0NCwERi4r4HTBC2mMSF
	e+vZQGxeAX2J54ungsVZBFQlTpzqBouzCehKTOpfAWYLCahI9J29AVbDLyAsse9DE9hMUYEQ
	iXNPvkPNEZQ4OfMJC4gtIqAt8ejNdUYQm1kgWOLs+m9gcWGBCIlFE5uBermAZk5llNj86D5Y
	EadAoMSyuQ1MEA22EhfmXGeBsOUltr+dwwxxhKrEiuaJbBAPKEj8v/KOaQKj0Cwku2chaZ+F
	pH0BI/MqRvHissTkjEzTguLckgJDvYLUxGwzvbzUkk2M4Cg+LbeDcfpSxUOMAhyMSjy8F07v
	9BdiTSwrrsw9xCjBwawkwlvlvMtfiDclsbIqtSg/vqg0J7X4EKMpMNAmMkuJJucDE0xeSbyh
	saGlqaWJmaW5sbGBkjjvmyvL/YUE0oHpITs1tSC1CKaPiYNTqoFxqUjoZr33S66YHlObuvmP
	+96v1R8SWrgNzZYezAt++bPiX/gEhW+1VVlJ67huBHBLWunJLT5n2PQ1y77o0Szz3JWzmfzr
	mfJ7Plqt1E26dFvwkfD8/gNtX+ceEjP/6dD3bGtr6ePcMkbzHrkZP5hWcv0ob4w7ke722F8k
	m71cb9ZHjhOLyyKUWIozEg21mIuKEwHBKgHs+AIAAA==
X-Pg-Spam-Score: -1.9 (-)
X-Archive-Number: 201205/112
X-Sequence-Number: 46936

On 05/21/2012 10:41 AM, Scott Marlowe wrote:

> How fast is the link to your SAN?  If it's Gigabit, then 80MB/s would
> be pretty reasonable.

Wow, I didn't even think of that. I was looking up specs on the SAN. :)

Those stats are pretty horrible for sequential reads. The SAN should 
improve random reads, not mercilessly ruin sequential.

That does sound like the problem, though.

-- 
Shaun Thomas
OptionsHouse | 141 W. Jackson Blvd. | Suite 500 | Chicago IL, 60604
312-444-8534
sthomas@optionshouse.com

______________________________________________

See http://www.peak6.com/email_disclaimer/ for terms and conditions related to this email