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

help / color / mirror / Atom feed
From: Bill Moran <wmoran@collaborativefusion.com>
To: Mark Mielke <mark@mark.mielke.cc>
Cc: david@lang.hm, Florian Weimer <fw@deneb.enyo.de>
Cc: Fernando Hevia <fhevia@ip-tel.com.ar>
Cc: pgsql-performance <pgsql-performance@postgresql.org>
Subject: Re: With 4 disks should I go for RAID 5 or RAID 10
Date: Thu, 27 Dec 2007 11:54:44 -0500
Message-ID: <20071227115444.07a9af3f.wmoran@collaborativefusion.com> (raw)
In-Reply-To: <4773C3AE.1060602@mark.mielke.cc>
References: <0f8201c847f6$08e15090$8f01010a@iptel.com.ar>
	<Pine.LNX.4.64.0712261317320.11785@asgard.lang.hm>
	<87zlvxnpkl.fsf@mid.deneb.enyo.de>
	<4772CA58.5050406@mark.mielke.cc>
	<Pine.LNX.4.64.0712261504310.11785@asgard.lang.hm>
	<4772CE34.2040608@mark.mielke.cc>
	<20071226171105.889f6146.wmoran@collaborativefusion.com>
	<4772D3DA.10302@mark.mielke.cc>
	<20071227085009.94ea3bef.wmoran@collaborativefusion.com>
	<4773C3AE.1060602@mark.mielke.cc>

In response to Mark Mielke <mark@mark.mielke.cc>:

> Bill Moran wrote:
> > In response to Mark Mielke <mark@mark.mielke.cc>:
> >
> >   
> >> Bill Moran wrote:
> >>     
> >>> I'm fairly sure that FreeBSD's GEOM does.  Of course, it couldn't be doing
> >>> consistency checking at that point.
> >>>       
> >> According to this:
> >>
> >> http://www.freebsd.org/cgi/man.cgi?query=gmirror&apropos=0&sektion=8&manpath=FreeBSD+6-c...
> >>
> >> There is a -b (balance) option that seems pretty clear that it does not 
> >> read from all drives if it does not have to:
> >>     
> >
> > >From where did you draw that conclusion?  Note that the "split" algorithm
> > (which is the default) divides requests up among multiple drives.  I'm
> > unclear as to how you reached a conclusion opposite of what the man page
> > says -- did you test and find it not to work?
> >   
> Perhaps you and I are speaking slightly different languages? :-) When I 
> say "does not read from all drives", I mean "it will happily read from 
> any of the drives to satisfy the request, and allows some level of 
> configuration as to which drive it will select. It does not need to read 
> all of the drives to satisfy the request."

Ahh ... I did misunderstand you.

-- 
Bill Moran
Collaborative Fusion Inc.
http://people.collaborativefusion.com/~wmoran/

wmoran@collaborativefusion.com
Phone: 412-422-3463x4023



view thread (37+ messages)

Message-ID: <20071227115444.07a9af3f.wmoran@collaborativefusion.com>
Permalink:  ../20071227115444.07a9af3f.wmoran@collaborativefusion.com/
Also on:    postgresql.org/message-id/20071227115444.07a9af3f.wmoran@collaborativefusion.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: wmoran@collaborativefusion.com, mark@mark.mielke.cc, fw@deneb.enyo.de, fhevia@ip-tel.com.ar
  Subject: Re: With 4 disks should I go for RAID 5 or RAID 10
  In-Reply-To: <20071227115444.07a9af3f.wmoran@collaborativefusion.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