Re: [Gluster-devel] Is it possible to setup a RAID 6 using GlusterFS?

[David Coulson]

You need to do 12 bricks across 4 nodes, in 'replica 3' groups. This 
would allow you to lose two nodes and still have access to all your 
data, as each distributed replica group is across at least 3 of your 4 
nodes.

You will need to be deliberate about which 3-way groups end up on each 
node so you have appropriate redundancy (e.g. group one does 1,2,3, 
group two does 1,3,4, three does 2,3,4, four does 1,2,4)

On 4/6/12 8:06 PM, Pascal wrote:
> Hello David,
>
> I hope that you will read this, even though your post was written some
> days ago.
>
> I was trying to configure your suggestion "with a replica count of 3"
> and I wasn't able to do it.
>
>
> My original setup with four nodes: node1, node2, node3, node4.
>
> # gluster volume create gluster-storage replica 2 transport tcp
> ip-node1:/data ip-node2:/data ip-node3:/data ip-node4:/data
>
> The result:
> Node1 and node2 replicated the files among each other and node3 and
> node4 did the same. The replication group of node1 and node2 (group1)
> distributed the files among the replication group of node3 and node4
> (group2).
>
> The problem:
> Two hard drives could fail at the same time, but just one hard drive
> from each replication group. My aim is to archive something were any two
> hard drives could fail.
>
>
> Trying to setup a replica count of 3 with my four nodes:
>
> # gluster volume create gluster-storage replica 3 transport tcp
> ip-node1:/data ip-node2:/data ip-node3:/data ip-node4:/data
> > number of bricks is not a multiple of replica count
> This means to my, that I would need six nodes/bricks and that would
> lead me to the same situation as before. Node1, node2 and node3 would
> build a replication group and node4, node5 and node6 would build the
> other replication group and both groups together would save all the
> data.
> I would still have the problem that two hard drives from one
> replication group weren't allowed to fail at the same time.
>
>
> Did I misunderstood your idea of a "replica count of 3"? Would you be
> so kind to explain it to me?
>
> Thanks in advance!
>
> Pascal
>
>
> Am Thu, 29 Mar 2012 10:47:38 -0400
> schrieb David Coulson<address@hidden>:
>
> > Try doing a distributed-replica with a replica count of 3. Not really
> > 'RAID-6' comparable, but you can have two nodes fail without outage.
> >
> > http://download.gluster.com/pub/gluster/glusterfs/3.2/Documentation/AG/html/sect-Administration_Guide--Setting_Volumes-Distributed_Replicated.html
> >
> > On 3/29/12 10:39 AM, Pascal wrote:
> > > Hello everyone,
> > >
> > > I would like to know if it is possible to setup a GlusterFS
> > > installation which is comparable to a RAID 6? I did some research in
> > > the community and several mailing lists and all I could find were
> > > the similar request from 2009
> > > (http://gluster.org/pipermail/gluster-users/2009-May/002208.html,
> > > http://www.gluster.org/community/documentation/index.ph/Talk:GlusterFS_Roadmap_Suggestions).
> > >
> > > I would just like to have a scenario where two GlusterFS
> > > nodes/servers, respectively their hard drives, could fail at the
> > > same time.
> > >
> > > Thanks in advance!
> > > Pascal
> > >
> > >
> > > _______________________________________________
> > > Gluster-devel mailing list
> > > address@hidden
> > > https://lists.nongnu.org/mailman/listinfo/gluster-devel
>
>
>
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