Hi, I have 4 servers each with 1TB of storage set as /dev/sdb1, I would like to set these up in a raid 10 which will? give me 2TB useable. So Mirrored and concatenated? The command I am running is as per documents but I get a warning error, how do I get this to proceed please as the documents do not say. gluster volume create gv0 replica 2 glusterp1:/bricks/brick1/gv0 glusterp2:/bricks/brick1/gv0 glusterp3:/bricks/brick1/gv0 glusterp4:/bricks/brick1/gv0 Replica 2 volumes are prone to split-brain. Use Arbiter or Replica 3 to avoid this. See: http://docs.gluster.org/en/latest/Administrator%20Guide/Split%20brain%20and%20ways%20to%20deal%20with%20it/ . Do you still want to continue? (y/n) n Usage: volume create <NEW-VOLNAME> [stripe <COUNT>] [replica <COUNT> [arbiter <COUNT>]] [disperse [<COUNT>]] [disperse-data <COUNT>] [redundancy <COUNT>] [transport <tcp|rdma|tcp,rdma>] <NEW-BRICK>?<vg_name>... [force] [root at glustep1 ~]# thanks -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.gluster.org/pipermail/gluster-users/attachments/20180427/68c015fc/attachment.html>
Milind Changire
2018-Apr-27 05:50 UTC
[Gluster-users] How to set up a 4 way gluster file system
On Fri, Apr 27, 2018 at 10:56 AM, Thing <thing.thing at gmail.com> wrote:> Hi, > > I have 4 servers each with 1TB of storage set as /dev/sdb1, I would like > to set these up in a raid 10 which will? give me 2TB useable. So Mirrored > and concatenated? > > The command I am running is as per documents but I get a warning error, > how do I get this to proceed please as the documents do not say. > > gluster volume create gv0 replica 2 glusterp1:/bricks/brick1/gv0 > glusterp2:/bricks/brick1/gv0 glusterp3:/bricks/brick1/gv0 > glusterp4:/bricks/brick1/gv0 > Replica 2 volumes are prone to split-brain. Use Arbiter or Replica 3 to > avoid this. See: http://docs.gluster.org/en/latest/Administrator%20Guide/ > Split%20brain%20and%20ways%20to%20deal%20with%20it/. > Do you still want to continue? > (y/n) n > >This is not an error. It is a recommendation and an explicit cautionary step to remind users of the problems using a replica 2. It is advisable to use a replica 3 instead of a replica 2 to avoid split-brain conditions. If you still insist on using a replica 2, you can go ahead and answer a 'y' to a the "Do you still want to continue ?" question.> Usage: > volume create <NEW-VOLNAME> [stripe <COUNT>] [replica <COUNT> [arbiter > <COUNT>]] [disperse [<COUNT>]] [disperse-data <COUNT>] [redundancy <COUNT>] > [transport <tcp|rdma|tcp,rdma>] <NEW-BRICK>?<vg_name>... [force] > > [root at glustep1 ~]# > > thanks > > _______________________________________________ > Gluster-users mailing list > Gluster-users at gluster.org > http://lists.gluster.org/mailman/listinfo/gluster-users >-- Milind -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.gluster.org/pipermail/gluster-users/attachments/20180427/d833e942/attachment.html>
Karthik Subrahmanya
2018-Apr-27 06:05 UTC
[Gluster-users] How to set up a 4 way gluster file system
Hi, With replica 2 volumes one can easily end up in split-brains if there are frequent disconnects and high IOs going on. If you use replica 3 or arbiter volumes, it will guard you by using the quorum mechanism giving you both consistency and availability. But in replica 2 volumes, quorum does not make sense since it needs both the nodes up to guarantee consistency, which costs availability. If you can consider having a replica 3 or arbiter volumes it would be great. Otherwise you can anyway go ahead and continue with the replica 2 volume by selecting *y* for the warning message. It will create the replica 2 configuration as you wanted. HTH, Karthik On Fri, Apr 27, 2018 at 10:56 AM, Thing <thing.thing at gmail.com> wrote:> Hi, > > I have 4 servers each with 1TB of storage set as /dev/sdb1, I would like > to set these up in a raid 10 which will? give me 2TB useable. So Mirrored > and concatenated? > > The command I am running is as per documents but I get a warning error, > how do I get this to proceed please as the documents do not say. > > gluster volume create gv0 replica 2 glusterp1:/bricks/brick1/gv0 > glusterp2:/bricks/brick1/gv0 glusterp3:/bricks/brick1/gv0 > glusterp4:/bricks/brick1/gv0 > Replica 2 volumes are prone to split-brain. Use Arbiter or Replica 3 to > avoid this. See: http://docs.gluster.org/en/latest/Administrator%20Guide/ > Split%20brain%20and%20ways%20to%20deal%20with%20it/. > Do you still want to continue? > (y/n) n > > Usage: > volume create <NEW-VOLNAME> [stripe <COUNT>] [replica <COUNT> [arbiter > <COUNT>]] [disperse [<COUNT>]] [disperse-data <COUNT>] [redundancy <COUNT>] > [transport <tcp|rdma|tcp,rdma>] <NEW-BRICK>?<vg_name>... [force] > > [root at glustep1 ~]# > > thanks > > _______________________________________________ > Gluster-users mailing list > Gluster-users at gluster.org > http://lists.gluster.org/mailman/listinfo/gluster-users >-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.gluster.org/pipermail/gluster-users/attachments/20180427/4bd304d4/attachment.html>
Hi, I have 4 nodes, so a quorum would be 3 of 4. The Q is I suppose why does the documentation give this command as an example without qualifying it? SO I am running the wrong command? I want a "raid10" On 27 April 2018 at 18:05, Karthik Subrahmanya <ksubrahm at redhat.com> wrote:> Hi, > > With replica 2 volumes one can easily end up in split-brains if there are > frequent disconnects and high IOs going on. > If you use replica 3 or arbiter volumes, it will guard you by using the > quorum mechanism giving you both consistency and availability. > But in replica 2 volumes, quorum does not make sense since it needs both > the nodes up to guarantee consistency, which costs availability. > > If you can consider having a replica 3 or arbiter volumes it would be > great. Otherwise you can anyway go ahead and continue with the replica 2 > volume > by selecting *y* for the warning message. It will create the replica 2 > configuration as you wanted. > > HTH, > Karthik > > On Fri, Apr 27, 2018 at 10:56 AM, Thing <thing.thing at gmail.com> wrote: > >> Hi, >> >> I have 4 servers each with 1TB of storage set as /dev/sdb1, I would like >> to set these up in a raid 10 which will? give me 2TB useable. So Mirrored >> and concatenated? >> >> The command I am running is as per documents but I get a warning error, >> how do I get this to proceed please as the documents do not say. >> >> gluster volume create gv0 replica 2 glusterp1:/bricks/brick1/gv0 >> glusterp2:/bricks/brick1/gv0 glusterp3:/bricks/brick1/gv0 >> glusterp4:/bricks/brick1/gv0 >> Replica 2 volumes are prone to split-brain. Use Arbiter or Replica 3 to >> avoid this. See: http://docs.gluster.org/en/lat >> est/Administrator%20Guide/Split%20brain%20and%20ways%20to% >> 20deal%20with%20it/. >> Do you still want to continue? >> (y/n) n >> >> Usage: >> volume create <NEW-VOLNAME> [stripe <COUNT>] [replica <COUNT> [arbiter >> <COUNT>]] [disperse [<COUNT>]] [disperse-data <COUNT>] [redundancy <COUNT>] >> [transport <tcp|rdma|tcp,rdma>] <NEW-BRICK>?<vg_name>... [force] >> >> [root at glustep1 ~]# >> >> thanks >> >> _______________________________________________ >> Gluster-users mailing list >> Gluster-users at gluster.org >> http://lists.gluster.org/mailman/listinfo/gluster-users >> > >-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.gluster.org/pipermail/gluster-users/attachments/20180427/33cef241/attachment.html>