MariaDB / Galera

#1

Anyone ever done any MariaDB Galera clustering / replication? Curious how that works.

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#2

Our current setup we have replication from Mysql server to a 2-node Galera cluster. We are eventually going to retire the current primary Mysql server (that did just replication to 2 other Mysql servers) and move to Galera cluster.

My first impression with Galera was surprised at how easy and fast it is to setup. This was not the case few years back when evaluating Oracle’s Mysql cluster. We have had a test Galera server for Ignition running since last summer, and another cluster for other use since then as well.

One thing this does provide is that now any server/node can be connected from Ignition. This is technically not the case with using standard replication. If the master goes down and you need to use the slave, this requires special considerations and intervention. When the master comes back up, it will technically be behind the slave, and thus on the slave you need promote that to master, make the master the slave. Not the case with Galera, node can be shut down at will, with only caveat being the longer it remains offline the longer it will take to synchronize with the node elected as primary.

FYI, I have not looked at Percona cluster, but Percona xtrabackup really does work great. In fact it was a Percona xtrabackup I was using to copy from the primary server to setup other servers and restart both replication on new servers as well as get the new Galera server up and running.

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#3

We have a project coming up where we will have redundant Ignition Servers running on Ubuntu. They will probably be running Ignition 8, because it should be out by then.

We are thinking of using Galera with a MariaDB instance on each GW.

Does anyone know if this will work well, or have updates about how Galera has worked for them?

Will there be any problems with resync when the Primary Ignition GW comes back up?

Thanks

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#4

We use Galera and MariaDB frequencly. It works quite well.

Servers in the cluster will re-synchronize when they boot back up, so long as quorum was maintained during the server outage.

Galera will not scale your writes. If you are using it for application availability, it will work great.

You will want to try to write to a single server at any given point in time.

I would recommend separating the ignition server from the database server, where possible.

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