[Gluster-users] adding a node

[JF Le Fillâtre]

Hi,

OK, I was confused because in your original email you mentioned "a
multiple of the striped so 4 other node".

So yes your stripe count is 2, so you have to add bricks 2 by 2, as the
error message says. If you didn't, then it would mean that you would
distribute your data over two 2-brick stripes, and one 1-brick single
volume, which I am reasonably sure wouldn't work.

If you want to be able to add bricks one by one, you would need a
regular distributed volume, without:
- striping (requires adding as many drives as stripe count)
- replication (requires adding as many drives as stripe replication count)
- dispersion (requires adding as many drives as whatever your dispersion
disk count is)

The only two things that you can extend is the number of brick groups in
a distributed volume, with a similar brick group, or the number of
replicas (but I'm sure that there are corner cases where you can't do
it, I haven't tried them yet).

Is that clearer now?

Thanks!
JF



On 16/03/15 16:56, Pierre Léonard wrote:
> Hi JF Le Fillâtre,
> 
> Hello,
> 
> You cannot. As the message said, you cannot change the stripe count.
> 
> I don't change the strip count, the number is the same. 
> 
> So
> you can add 4 bricks and you have a distributed + striped volume, but
> you cannot change the stripe count by re-adding existing bricks into the
> volume with a different stripe count, or by adding an additional brick
> to the volume.
> 
> That is the real question : "is it possible to add a node to a stripe volume one by one ?"
> I not when I receive a new node I can't insert it in the global cluster service !
> 
> 
>  Your email isn't very clear; could you please send:
> - the list of commands in the order that you typed them;
> - the output of "gluster volume info" and "gluster volume status"
> 
> On one of the four node :
> [root at boogy2 ~]# gluster volume stop gvHome
> 
> on the new node :
> [root at moody gvHome]# gluster volume add-brick gvHome  moody:/mnt/gvHome/brick1
> volume add-brick: failed: Incorrect number of bricks supplied 1 with count 2
> 
> [root at boogy2 ~]# gluster volume info gvHome
> 
> Volume Name: gvHome
> Type: Distributed-Stripe
> Volume ID: aa7bc5be-e6f6-43b0-bba2-b9d51ed2e4ef
> Status: Started
> Number of Bricks: 2 x 2 = 4
> Transport-type: tcp
> Bricks:
> Brick1: boogy1:/mnt/gvHome/brick1
> Brick2: boogy2:/mnt/gvHome/brick1
> Brick3: boogy3:/mnt/gvHome/brick1
> Brick4: boogy4:/mnt/gvHome/brick1
> 
> 
> [root at boogy2 ~]# gluster volume status gvHome
> Status of volume: gvHome
> Gluster process                                         Port    Online  Pid
> ------------------------------------------------------------------------------
> Brick boogy1:/mnt/gvHome/brick1                         49153   Y       21735
> Brick boogy2:/mnt/gvHome/brick1                         49153   Y       121607
> Brick boogy3:/mnt/gvHome/brick1                         49153   Y       26828
> Brick boogy4:/mnt/gvHome/brick1                         49153   Y       116839
> NFS Server on localhost                                 N/A     N       N/A
> NFS Server on moody                                     N/A     N       N/A
> NFS Server on 138.102.172.94                            2049    Y       116853
> NFS Server on boogy1                                    2049    Y       21749
> NFS Server on boogy3                                    2049    Y       26843
> 
> Task Status of Volume gvHome
> ------------------------------------------------------------------------------
> There are no active volume tasks
> 
> 
> 
> [root at boogy2 ~]# glusterd -V
> glusterfs 3.6.1 built on Nov  7 2014 15:15:48
> 
> 
> that's all.
> 
> 
> Many thank's
> 
> sincereley
> 
> -- 
> Signature electronique
> INRA <http://www.inra.fr>
>  
> *Pierre Léonard*
> *Senior IT Manager*
> *MetaGenoPolis*
> Pierre.Leonard at jouy.inra.fr <mailto:Pierre.Leonard at jouy.inra.fr>
> Tél. : +33 (0)1 34 65 29 78
> 
> Centre de recherche INRA
> Domaine de Vilvert – Bât. 325 R+1
> 78 352 Jouy-en-Josas CEDEX
> France
> www.mgps.eu <http://www.mgps.eu>
> 

-- 

 Jean-François Le Fillâtre
 -------------------------------
 HPC Systems Administrator
 LCSB - University of Luxembourg
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