Message-ID: <43AFB641.6070009@cs.ucr.edu>
Date: Mon, 26 Dec 2005 01:22:09 -0800
From: Benjamin Arai <barai@cs.ucr.edu>
User-Agent: Mozilla Thunderbird 1.0.6 (Windows/20050716)
MIME-Version: 1.0
Cc: pgsql-performance@postgresql.org
Subject: Re: What's the best hardver for PostgreSQL 8.1?
References: <3E37B936B592014B978C4415F90D662D01F1B59F@MI8NYCMAIL06.Mi8.com>
In-Reply-To: <3E37B936B592014B978C4415F90D662D01F1B59F@MI8NYCMAIL06.Mi8.com>
Content-Type: multipart/alternative;
	boundary="------------050301090903080409000002"

This is a multi-part message in MIME format.
--------------050301090903080409000002
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit

Have you done any benchmarking of the 9550SX against a software raid 
configuration? 

Luke Lonergan wrote:

>Frank, 
>
>  
>
>>  You definitely DO NOT want to do RAID 5 on a database server.  That
>>  is probably the worst setup you could have, I've seen it have lower
>>  performance than just a single hard disk. 
>>    
>>
>
>I've seen that on RAID0 and RAID10 as well.
>
>This is more about the quality and modernity of the RAID controller than
>anything else at this point, although there are some theoretical
>advantages of RAID10 from a random seek standpoint even if the adapter
>CPU is infinitely fast at checksumming.  We're using RAID5 in practice
>for OLAP / Data Warehousing systems very successfully using the newest
>RAID cards from 3Ware (9550SX).
>
>Note that host-based SCSI raid cards from LSI, Adaptec, Intel, Dell, HP
>and others have proven to have worse performance than a single disk
>drive in many cases, whether for RAID0 or RAID5.  In most circumstances
>I've seen, people don't even notice until they write a message to a
>mailing list about "my query runs slowly on xxx dbms".  In many cases,
>after they run a simple sequential transfer rate test using dd, they see
>that their RAID controller is the culprit.
>
>Recently, I helped a company named DeepData to improve their dbms
>performance, which was a combination of moving them to software RAID50
>on Linux and getting them onto Bizgres.  The disk subsystem sped up on
>the same hardware (minus the HW RAID card) by over a factor of 10.  The
>downside is that SW RAID is a pain in the neck for management - you have
>to shut down the Linux host when a disk fails to replace it.
>
>- Luke
>
>
>---------------------------(end of broadcast)---------------------------
>TIP 6: explain analyze is your friend
>  
>

-- 
*Benjamin Arai*
barai@cs.ucr.edu <emailto:barai@cs.ucr.edu>
http://www.benjaminarai.com

--------------050301090903080409000002
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
  <meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
</head>
<body bgcolor="#ffffff" text="#000000">
Have you done any benchmarking of the 9550SX against a software raid
configuration?&nbsp; <br>
<br>
Luke Lonergan wrote:
<blockquote
 cite="mid3E37B936B592014B978C4415F90D662D01F1B59F@MI8NYCMAIL06.Mi8.com"
 type="cite">
  <pre wrap="">Frank, 

  </pre>
  <blockquote type="cite">
    <pre wrap="">  You definitely DO NOT want to do RAID 5 on a database server.  That
  is probably the worst setup you could have, I've seen it have lower
  performance than just a single hard disk. 
    </pre>
  </blockquote>
  <pre wrap=""><!---->
I've seen that on RAID0 and RAID10 as well.

This is more about the quality and modernity of the RAID controller than
anything else at this point, although there are some theoretical
advantages of RAID10 from a random seek standpoint even if the adapter
CPU is infinitely fast at checksumming.  We're using RAID5 in practice
for OLAP / Data Warehousing systems very successfully using the newest
RAID cards from 3Ware (9550SX).

Note that host-based SCSI raid cards from LSI, Adaptec, Intel, Dell, HP
and others have proven to have worse performance than a single disk
drive in many cases, whether for RAID0 or RAID5.  In most circumstances
I've seen, people don't even notice until they write a message to a
mailing list about "my query runs slowly on xxx dbms".  In many cases,
after they run a simple sequential transfer rate test using dd, they see
that their RAID controller is the culprit.

Recently, I helped a company named DeepData to improve their dbms
performance, which was a combination of moving them to software RAID50
on Linux and getting them onto Bizgres.  The disk subsystem sped up on
the same hardware (minus the HW RAID card) by over a factor of 10.  The
downside is that SW RAID is a pain in the neck for management - you have
to shut down the Linux host when a disk fails to replace it.

- Luke


---------------------------(end of broadcast)---------------------------
TIP 6: explain analyze is your friend
  </pre>
</blockquote>
<br>
<div class="moz-signature">-- <br>
<b>Benjamin Arai</b><br>
<a href="emailto:barai@cs.ucr.edu">barai@cs.ucr.edu</a><br>
<a href="http://www.benjaminarai.com">http://www.benjaminarai.com</a>
</div>
</body>
</html>

--------------050301090903080409000002--