From: Joshua D. Drake <jd@commandprompt.com>
To: PFC <lists@boutiquenumerique.com>
Cc: Dave Cramer <pg@fastcrypt.com>
Cc: Michael Ben-Nes <miki@canaan.co.il>
Cc: pgsql-performance@postgresql.org
Subject: Re: Advice on RAID card
Date: Sun, 25 Sep 2005 09:22:02 -0700
Message-ID: <4336CEAA.7070208@commandprompt.com> (raw)
In-Reply-To: <op.sxn1sdofth1vuj@localhost>
References: <IGEGINLEEDLANNHAAKCMOECJCCAA.gaulakh@ecmarket.com>
<op.sxll3du6th1vuj@localhost>
<43367937.40809@canaan.co.il>
<ABE6B997-2C1E-43B1-9F18-28F54B1620FE@fastcrypt.com>
<4336C57B.6090800@commandprompt.com>
<op.sxn1sdofth1vuj@localhost>
>
> Even for RAID5 ? it uses a bit more CPU for the parity calculations.
I honestly can't speak to RAID 5. I don't (and won't) use it. RAID 5 is
a little brutal when under
heavy write load. I use either 1, or 10.
> An advantage of software raid, is that if the RAID card dies, you
> have to buy the same one ; whether I think that you can transfer a
> bunch of software RAID5 disks to another machine if the machine
> they're in dies...
There is a huge advantage to software raid on all kinds of levels. If
you have the CPU then I suggest
it. However you will never get the performance out of software raid on
the high level (think 1 gig of cache)
that you would on a software raid setup.
It is a bit of a tradeoff but for most installations software raid is
more than adequate.
Sincerely,
Joshua D. Drake
--
Your PostgreSQL solutions company - Command Prompt, Inc. 1.800.492.2240
PostgreSQL Replication, Consulting, Custom Programming, 24x7 support
Managed Services, Shared and Dedicated Hosting
Co-Authors: plPHP, plPerlNG - http://www.commandprompt.com/
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: jd@commandprompt.com, lists@boutiquenumerique.com, pg@fastcrypt.com, miki@canaan.co.il
Subject: Re: Advice on RAID card
In-Reply-To: <4336CEAA.7070208@commandprompt.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