maria-discuss team mailing list archive

[Alex Yurchenko <alexey.yurchenko@xxxxxxxxxxxxx>]

On 2014-01-03 21:50, AskMonty KB wrote:
> Hello,
>
> A new question has been asked in "MariaDB FAQ" by pranava:
> --------------------------------
> I have some questions on Maria DB Galera Cluster.
>
> Q1) If I partition a table in a schema which is part of MariaDB Galera
> Cluster, can i configure partitions in such a way that a one partition
> resides in one Node, another partition resides in second Node and so
> on? I'm trying to shard the data and use Galera cluster nodes to
> accommodate parts of that shard.

No, it is a design assumption that every node holds all the data, so all 
nodes are identical.

> Q2) Scenario - During replication of MariaDB Galera Cluster, the
> Master node gets a request, it processes it and then sends to other
> nodes for approval, followed by a commit at every node. What if commit
> happens on majority of nodes except one or two? What happens to that
> transaction and how about Data consistency among all nodes?

A deterministic certification algorithm is used to determine whether 
transaction must be committed or not. So all nodes are guaranteed to 
decide identically. If a node decides that transaction should be 
(applied and) committed but for some reason can't do it, it assumes data 
inconsistency and aborts.

> Q3) Which protocol is used for communicating between nodes during data
> replication in MariaDB Galera Cluster? Is it TCP or a Broadcast to all
> other nodes or Some customized protocol between nodes that enables
> replication in the cluster.

It is a proprietary group communication protocol on top of TCP or UDP 
multicast.

Regards,
Alex

> Thanks a lot in advance.
>
> Thanks
> Pranav.
> --------------------------------
>
> To view or answer this question please visit:
> http://mariadb.com/kb/en/mariadb-galera-cluster-questions/
>
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--
Alexey Yurchenko,
Codership Oy, www.codership.com
Skype: alexey.yurchenko, Phone: +358-400-516-011