[Gluster-users] adding bricks of diferent size to gluster

[samuel]

I'll read through the provided links.

thanks very much indeed, Dan!

Samuel.

On 5 March 2012 13:29, Dan Bretherton <d.a.bretherton at reading.ac.uk> wrote:

>
> On 03/05/2012 09:39 AM, gluster-users-request at gluster.**org<gluster-users-request at gluster.org>wrote:
>
>> Date: Mon, 5 Mar 2012 10:29:22 +0100
>> From: samuel<samu60 at gmail.com>
>> Subject: [Gluster-users] adding bricks of diferent size to gluster
>> To:gluster-users at gluster.org
>> Message-ID:
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>>
>> Dear all,
>>
>> I've been trying to locate documentation about gluster functionality about
>> using bricks of diferent sizes and did not find anything useful.
>>
>> What I was trying to answer was:
>>
>> *How does using bricks of different size in a distributed replicated
>> volume
>> affects performance?
>>
>> I think I read somewhere that it was highly advisable to use bricks of the
>> same size but I can not locate where I read such statement? Is it true?
>>
>> Case it's depending on the version, I'm using mostly 3.2.4 version.
>>
>> Thank in advance,
>> Samuel.
>>
> Samuel,
> The mechanism described in the following gluster-users posting describes
> how non uniform brick sizes are managed by GlusterFS.
>
> http://gluster.org/pipermail/**gluster-users/2011-September/**008754.html<http://gluster.org/pipermail/gluster-users/2011-September/008754.html>
>
> 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.
>
> http://gluster.org/pipermail/**gluster-users/2011-May/007788.**html<http://gluster.org/pipermail/gluster-users/2011-May/007788.html>
>
> The posting below describes how I have set up uniform brick sizes despite
> having different sized servers in my cluster.
>
> http://gluster.org/pipermail/**gluster-users/2011-August/**008597.html<http://gluster.org/pipermail/gluster-users/2011-August/008597.html>
>
> 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.
>
> http://gluster.org/pipermail/**gluster-users/2011-November/**009176.html<http://gluster.org/pipermail/gluster-users/2011-November/009176.html>
>
> 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.
>
> http://gluster.org/pipermail/**gluster-users/2011-May/007794.**html<http://gluster.org/pipermail/gluster-users/2011-May/007794.html>
> http://gluster.org/pipermail/**gluster-users/2011-August/**008579.html<http://gluster.org/pipermail/gluster-users/2011-August/008579.html>
>
> 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.
>
>
> I hope this helps.
> -Dan.
>
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