Hello David, thank you for explaining it. To sum it up: Your suggestion works like a charm ;) I still have a follow-up question. I expected the available storage capacity to be half of the total storage capacity provided by all brick partitions/volumes. In my test environment each of the four bricks provides ~16 GB and if two nodes could fail at the same time, there would just ~32 GB be left. So I used the df command on a client ... # df -h /mn/gluster-volume ... and it shows me that ~64 GB are available. I am not able to store files of a total size of 64 GB on that volume, isn't it? Can someone explain the result of df to me? ---------- I am not sure, if it is the usual way to write down "solutions" on the mailing list, but I thing it could be helpful for other people. node1 - /data - /exp1 - /exp2 - /exp3 node2 - /data - /exp1 - /exp2 - /exp3 node3 - /data - /exp1 - /exp2 - /exp3 node4 - /data - /exp1 - /exp2 - /exp3 # gluster volume create gluster-volume replica 3 transport tcp \ node1:/data/exp1 node2:/data/exp1 node3:/data/exp1 \ node1:/data/exp2 node2:/data/exp2 node4:/data/exp1 \ node1:/data/exp3 node3:/data/exp2 node4:/data/exp2 \ node2:/data/exp3 node3:/data/exp3 node4:/data/exp3 Am Fri, 06 Apr 2012 21:04:16 -0400 schrieb David Coulson <david@xxxxxxxxxxxxxxxx>: > 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<david@xxxxxxxxxxxxxxxx>: > > > >> 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
