[Gluster-users] Expanding a distributed disperse volume: some questions about the action plan

[Mauro Tridici]

Hi Serkan,

thank you very much for your answer.
I really appreciate your suggestion (extension + rebalance + upgrade), but we would like to avoid any errors or risks of data loss during the upgrade procedure (we don’t have an advanced experience and we don’t know what to do if something goes wrong).
Currently, our Gluster volume contains a lot of consolidated and important scientific data and, unfortunately, we didn’t yet activate the Gluster support.

Thank you for sharing with me your opinion.
Regards,
Mauro



> Il giorno 07 giu 2018, alle ore 15:49, Serkan Çoban <cobanserkan at gmail.com> ha scritto:
> 
>> in order to copy the data from the old volume to the new one, I need a third machine that can mount both the volumes; it's possible? if yes, which gluster client version should I use/install on the "bridge" machine?
> Yes it is possible, you need to install old client version to bridge
> server, old clients can talk to new servers
> 
> Why not just extend the old cluster & rebalance and then upgrade to
> latest version of glusterfs?
> 
> On Thu, Jun 7, 2018 at 3:18 PM, Mauro Tridici <mauro.tridici at cmcc.it> wrote:
>> Dear Users,
>> 
>> just one year ago, we implemented a tier2 storage based on GlusterFS
>> v.3.10.5 and we can say that it works like a charm.
>> The GlusterFS volume has been created using 3 physical servers (each server
>> contains 12 disks, 1 brick per disk).
>> 
>> Below, you can find some information about the gluster volume type
>> 
>> Volume Name: tier2
>> Type: Distributed-Disperse
>> Volume ID: a28d88c5-3295-4e35-98d4-210b3af9358c
>> Status: Started
>> Snapshot Count: 0
>> Number of Bricks: 6 x (4 + 2) = 36
>> Transport-type: tcp
>> 
>> Now, it's time to expand this volume so we bought 3 new servers similar to
>> the 3 existing servers. Since we would like to upgrade the Gluster version
>> to last available one, we would like to know if the following action plan is
>> correct and safe:
>> 
>> 1) creation of a new gluster distributed disperse volume (6x(4+2)) using the
>> 3 new servers and the new gluster version;
>> 2) copy of all the data saved on the old gluster volume to the new one;
>> 3) complete erasure of three old servers operating system;
>> 4) installation of the last available version of the operating system and
>> glusterfs software stack on the three old servers;
>> 5) expansion of the volume (created at point nr.1) adding the new bricks
>> (created at point nr.4)
>> 
>> If our action plan can be considered "validated", I have an other question:
>> 
>> - in order to copy the data from the old volume to the new one, I need a
>> third machine that can mount both the volumes; it's possible? if yes, which
>> gluster client version should I use/install on the "bridge" machine?
>> 
>> Thank you very much for your attention.
>> Regards,
>> Mauro
>> 
>> 
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>> Gluster-users at gluster.org
>> http://lists.gluster.org/mailman/listinfo/gluster-users


-------------------------
Mauro Tridici

Fondazione CMCC
CMCC Supercomputing Center
presso Complesso Ecotekne - Università del Salento -
Strada Prov.le Lecce - Monteroni sn
73100 Lecce  IT
http://www.cmcc.it

mobile: (+39) 327 5630841
email: mauro.tridici at cmcc.it

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