Re: [ovirt-users] 4-node oVirt with replica-3 gluster
On Fri, Sep 23, 2016 at 7:09 PM, Davide Ferrari <davide(a)billymob.com> wrote:
2016-09-23 13:50 GMT+02:00 Sahina Bose <sabose(a)redhat.com>:
Ok, if I encounter again similiar problems I will post logs here
>
> If you have additional capacity on the other 3 hosts , then yes, you can
> create a new gluster volume with a brick on the newly added 4th node and
> bricks from other nodes - this volume can be used as another storage
> domain. You are not doing anything wrong :) Keep in mind that all gluster
> volumes used as data storage domains should be replica 3 or replica 3
> -arbiter to avoid split-brain and data loss issues.
>
>
Mmmmh this is ringing an alarm bell then. So, it's basically impossible
(or at least not supported) a 4 hosts configuration with all the 4 hosts
having a data domain in a replica 2 fashion? Is it only replica 3 arbiter 1
the supported HA configuration? So if I want to expand storage (a part from
adding disks to the same machines) I must add machines 3 by 3 ?
Currently I have 4 machines with 4 disks each in a RAID-10 configuration,
exposed as one brick. Which is the best HA solution in this scenario then?
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
Thanks
--
Davide Ferrari
Senior Systems Engineer
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