MariaDB Galera Cluster Or standard replication

Question

My question is simple :

• I have 2 servers, both are identical with proxy, apache, MariaDB,...etc.
• I have one IP Failover : the IP is routing to my first server but if this server falls down I will change the routing to the second server.

I try to install MariaDB Galera Cluster but is there a real advantage ?

In fact, I would like to know what kind of replication I have to use for MariaDB between both server for my use :

• MariaDB Galera Cluster
• Standard replication Master-Master
• Standard replication Master-Slave

And why ?

Thank you.

[EDIT]

If I install MariaDB Galera Cluster, I have 2 solutions :

• I can do 2 virtual servers on each 2 servers and I will have one node on each virtual servers so 4 nodes.

• I can do one node on each 2 servers so 2 nodes but it seems I have to install Galera Arbitrator, that's right ? But do I need a third server for that ?

What is the best way ?

Answer 1

M-M and M-S do not necessarily recover the database servers after various kinds of crashes. Galera does.

Your IP failover probably does fine for re-establishing a connection to a database server.

Galera needs 3 nodes (or 2 plus a lightweight "garbd") to avoid the "split-brain" situation that is a show stopper for standard replication.

Read up on those things, then see if you have a deeper question.

[EDIT]

If you have two Galera nodes on a single physical server, and that server goes down, Galera will assume "split brain: and the third Galera Node will stop accepting writes until you manually intervene.

A 4-node Galera Cluster needs to be tuned correctly, else if two nodes go down, it will similarly assume split brain. The trick is to weight some nodes more than others, thereby surviving some 2-node crashes.

More Galera tips, but mostly aimed at developers and DBAs.