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Date: Thu, 11 Sep 2008 16:20:19 -0700
From: "Scott Carey" <scott@richrelevance.com>
To: "Alan Hodgson" <ahodgson@simkin.ca>
Subject: Re: Effects of setting linux block device readahead size
Cc: pgsql-performance@postgresql.org
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I also thought that LVM is unsafe for WAL logs and file system journals with
disk write cache -- it doesn't flush the disk write caches correctly and
build write barriers.

As pointed out here:
http://groups.google.com/group/pgsql.performance/browse_thread/thread/9dc43991c1887129
by Greg Smith
http://lwn.net/Articles/283161/



On Thu, Sep 11, 2008 at 3:41 PM, Alan Hodgson <ahodgson@simkin.ca> wrote:

> On Thursday 11 September 2008, david@lang.hm wrote:
> > while I agree with you in theory, in practice I've seen multiple
> > partitions cause far more problems than they have prevented (due to the
> > partitions ending up not being large enough and having to be resized
> > after they fill up, etc) so I tend to go in the direction of a few large
> > partitions.
>
> I used to feel this way until LVM became usable. LVM plus online resizable
> filesystems really makes multiple partitions manageable.
>
>
> --
> Alan
>
> --
> Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org)
> To make changes to your subscription:
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<div dir="ltr">I also thought that LVM is unsafe for WAL logs and file system journals with disk write cache -- it doesn&#39;t flush the disk write caches correctly and build write barriers. <br><br>As pointed out here:<br>
<a href="http://groups.google.com/group/pgsql.performance/browse_thread/thread/9dc43991c1887129">http://groups.google.com/group/pgsql.performance/browse_thread/thread/9dc43991c1887129</a><br>by Greg Smith<br><a href="http://lwn.net/Articles/283161/">http://lwn.net/Articles/283161/</a><br>
<br><br><br><div class="gmail_quote">On Thu, Sep 11, 2008 at 3:41 PM, Alan Hodgson <span dir="ltr">&lt;<a href="mailto:ahodgson@simkin.ca">ahodgson@simkin.ca</a>&gt;</span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div class="Ih2E3d">On Thursday 11 September 2008, <a href="mailto:david@lang.hm">david@lang.hm</a> wrote:<br>
&gt; while I agree with you in theory, in practice I&#39;ve seen multiple<br>
&gt; partitions cause far more problems than they have prevented (due to the<br>
&gt; partitions ending up not being large enough and having to be resized<br>
&gt; after they fill up, etc) so I tend to go in the direction of a few large<br>
&gt; partitions.<br>
<br>
</div>I used to feel this way until LVM became usable. LVM plus online resizable<br>
filesystems really makes multiple partitions manageable.<br>
<br>
<br>
--<br>
<font color="#888888">Alan<br>
</font><div><div></div><div class="Wj3C7c"><br>
--<br>
Sent via pgsql-performance mailing list (<a href="mailto:pgsql-performance@postgresql.org">pgsql-performance@postgresql.org</a>)<br>
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</div></div></blockquote></div><br></div>

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