I'll read through the provided links.<br><br>thanks very much indeed, Dan!<br><br>Samuel.<br><br><div class="gmail_quote">On 5 March 2012 13:29, Dan Bretherton <span dir="ltr"><<a href="mailto:d.a.bretherton@reading.ac.uk">d.a.bretherton@reading.ac.uk</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><br>
On 03/05/2012 09:39 AM, <a href="mailto:gluster-users-request@gluster.org" target="_blank">gluster-users-request@gluster.<u></u>org</a> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Date: Mon, 5 Mar 2012 10:29:22 +0100<br>
From: samuel<<a href="mailto:samu60@gmail.com" target="_blank">samu60@gmail.com</a>><br>
Subject: [Gluster-users] adding bricks of diferent size to gluster<br>
<a href="mailto:To%3Agluster-users@gluster.org" target="_blank">To:gluster-users@gluster.org</a><br>
Message-ID:<br>
<CAOg=<a href="mailto:WDch3b72zN54B-11jQ_FPbF6MDe8qV86p1KfBG4jY76Mjg@mail.gmail.com" target="_blank">WDch3b72zN54B-11jQ_<u></u>FPbF6MDe8qV86p1KfBG4jY76Mjg@<u></u>mail.gmail.com</a>><br>
Content-Type: text/plain; charset="iso-8859-1"<div><div class="h5"><br>
<br>
Dear all,<br>
<br>
I've been trying to locate documentation about gluster functionality about<br>
using bricks of diferent sizes and did not find anything useful.<br>
<br>
What I was trying to answer was:<br>
<br>
*How does using bricks of different size in a distributed replicated volume<br>
affects performance?<br>
<br>
I think I read somewhere that it was highly advisable to use bricks of the<br>
same size but I can not locate where I read such statement? Is it true?<br>
<br>
Case it's depending on the version, I'm using mostly 3.2.4 version.<br>
<br>
Thank in advance,<br>
Samuel.<br>
</div></div></blockquote>
Samuel,<br>
The mechanism described in the following gluster-users posting describes how non uniform brick sizes are managed by GlusterFS.<br>
<br>
<a href="http://gluster.org/pipermail/gluster-users/2011-September/008754.html" target="_blank">http://gluster.org/pipermail/<u></u>gluster-users/2011-September/<u></u>008754.html</a><br>
<br>
I don't know if this approach carries a performance penalty, but I decided to move away from non uniform brick sizes because this configuration is not rigorously tested by the developers, as explained in the gluster-users posting below.<br>
<br>
<a href="http://gluster.org/pipermail/gluster-users/2011-May/007788.html" target="_blank">http://gluster.org/pipermail/<u></u>gluster-users/2011-May/007788.<u></u>html</a><br>
<br>
The posting below describes how I have set up uniform brick sizes despite having different sized servers in my cluster.<br>
<br>
<a href="http://gluster.org/pipermail/gluster-users/2011-August/008597.html" target="_blank">http://gluster.org/pipermail/<u></u>gluster-users/2011-August/<u></u>008597.html</a><br>
<br>
If you are considering using non uniform brick sizes please make sure that you set the min-free-disk parameter to an appropriate value in gigabytes. I originally had non uniform brick sizes in my cluster and I had a lot of problems with small bricks filling up before larger bricks, resulting in "device full" errors even when there was plenty of space left in the volume. The solution I eventually found is described in the following gluster-users posting.<br>
<br>
<a href="http://gluster.org/pipermail/gluster-users/2011-November/009176.html" target="_blank">http://gluster.org/pipermail/<u></u>gluster-users/2011-November/<u></u>009176.html</a><br>
<br>
The "device full" problem was caused by the default value of min-free-disk being defined as a percentage rather than as a value in gigabytes. To set the min-free-disk parameter to a value in GB follow the instructions described in the following gluster-users postings.<br>
<br>
<a href="http://gluster.org/pipermail/gluster-users/2011-May/007794.html" target="_blank">http://gluster.org/pipermail/<u></u>gluster-users/2011-May/007794.<u></u>html</a><br>
<a href="http://gluster.org/pipermail/gluster-users/2011-August/008579.html" target="_blank">http://gluster.org/pipermail/<u></u>gluster-users/2011-August/<u></u>008579.html</a><br>
<br>
It is important to make sure the value of min-free-disk is big enough. I found that setting the value to 10% of the size of the smallest brick seemed to work, but when I set it to only ~1% of the brick size I still had problems with "device full" errors.<br>
<br>
<br>
I hope this helps.<span class="HOEnZb"><font color="#888888"><br>
-Dan.<br>
</font></span></blockquote></div><br>