Re: [ovirt-users] 4-node oVirt with replica-3 gluster

On Fri, Sep 23, 2016 at 7:54 PM, Davide Ferrari <davide(a)billymob.com&gt; wrote: > Reading the glusterfs docs > > https://gluster.readthedocs.io/en/latest/Administrator%20Gui > de/arbiter-volumes-and-quorum/ > > "In a replica 3 volume, client-quorum is enabled by default and set to > 'auto'. This means 2 bricks need to be up for the writes to succeed. Here > is how this configuration prevents files from ending up in split-brain:" > > So this means that if one of the machines with the 2 bricks (arbiter & > normal) fails, the otherbrick will be set RO, or am I missing something? > I mean, this config will be better in case of a network loss, and thus a > split brain, but it's far worse in case of a machine failing or being > rebooted for maintenance. > See the updated vol create command - you should set it up such that 2 bricks in a sub-volume are not from the same host, thus you avoid the problem you describe above > > > 2016-09-23 16:11 GMT+02:00 Davide Ferrari <davide(a)billymob.com&gt;: > >> >> >> 2016-09-23 15:57 GMT+02:00 Sahina Bose <sabose(a)redhat.com&gt;: >> >>> >>> You could do this - where Node3 & Node 2 also has arbiter bricks. >>> Arbiter bricks only store metadata and requires very low storage capacity >>> compared to the data bricks. >>> >>> Node1 Node2 Node3 Node4 >>> brick1 brick1 arb-brick >>> arb-brick brick1 brick1 >>> >> >> Ok, cool! And this won't pose any problem if Node2 or Node4 fail? >> >> The syntax shuld be this: >> >> gluster volume create data replica 3 arbiter 1 node1:/brick node2:/brick >> node2:/arb_brick node3:/brick node4:/brick node4:/arb_brick >> >> is not a problem having more than a brick on the same host for the >> volume create syntax? >> >> Thanks again >> >> -- >> Davide Ferrari >> Senior Systems Engineer >> > > > > -- > Davide Ferrari > Senior Systems Engineer >