From: Greg Smith <greg@2ndquadrant.com>
To: Dan Birken <birken@gmail.com>
Cc: Scott Marlowe <scott.marlowe@gmail.com>
Cc: pgsql-performance <pgsql-performance@postgresql.org>
Subject: Re: Which RAID Controllers to pick/avoid?
Date: Thu, 03 Feb 2011 10:02:21 -0500
Message-ID: <4D4AC37D.2070207@2ndquadrant.com> (raw)
In-Reply-To: <AANLkTinFaFU=RUtfddYODoV9yHj-TfFc2XL7stg=NZaQ@mail.gmail.com>
References: <AANLkTimyRh1ieWxpCo1ht2D1fkmL+Ca_8ABBEw6yN2WR@mail.gmail.com>
<4D4A411A.3040102@2ndquadrant.com>
<AANLkTinB98Wgk+pzA_A9Ro=LTtmJJXFrkLVVM6h_d+AP@mail.gmail.com>
<4D4A4804.3040307@2ndquadrant.com>
<AANLkTinFaFU=RUtfddYODoV9yHj-TfFc2XL7stg=NZaQ@mail.gmail.com>
Dan Birken wrote:
> - Is the supercap + flash memory considered superior to the BBU in
> practice? Is that type of system well tested?
The main risk is that it's a pretty new approach. The standard BBU
setup has been used for a long time now; this whole flash+supercap thing
has only showed up in the last couple of years. Theoretically it's
better; the #1 weakness of the old battery setup was only surviving an
outage of a few days, and storing to flash doesn't have that issue.
It's just got the usual risks of something new.
> - Is the linux support of the LSI and Adaptec cards comparable?
Seems to be. The latest versions of Adaptec's arcconf utility even
provide about the same quality of command-line tools as LSI's megactl,
after being behind in that area for a while. Only quirk, and I can't
say where this was the manufacturer of the box or not because they
installed the base OS, is that the 5405 setup I saw didn't turn off the
write caches on the individual drives of the system. That's the
standard safe practice and default for the LSI cards.
--
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
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: greg@2ndquadrant.com, birken@gmail.com, scott.marlowe@gmail.com
Subject: Re: Which RAID Controllers to pick/avoid?
In-Reply-To: <4D4AC37D.2070207@2ndquadrant.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