Unfortunately I move to a different company and they are stick to MySQL For what I understand they have some mysql cluster without automatic failover. Probably also their customers have some kind of cluster without automatic failover.
Looking at some Galera cluster designs on web seems a couple of server proxy are placed in front. If I would have only 3 nodes where I clustered MySQL with galera how then I have to point my application to the right nodes? On Wed, Sep 6, 2023, 1:32 PM Antony Stone <antony.st...@ha.open.source.it> wrote: > On Wednesday 06 September 2023 at 12:10:23, Damiano Giuliani wrote: > > > Thanks for helping me. > > > > I'm going to know more about Galera. > > What I don't like is seems I need many nodes, at least 3 for the cluster > > and then at least 2 other nodes for proxy. > > You didn't mention anything about wanting a proxy service in your original > posting, and there's no reason why a proxy can't run on the same machines > as > MySQL does. > > As for requiring three nodes, you'll need that for pacemaker anyway. > Trying > to run a 2-node cluster (of anything) as a production service is a > disaster > waiting to happen. Read up about "split brain" if you do not know why. > > > Asking for 5 VM is quite consuming. > > What's your actual (functional) requirement here? > > > As you told drbd can work only in 2 node cluster and disk replication is > > not dbms replication. > > Probably I'm going to try drbd on very small and low usage db. > > The lower the usage (and therefore unrepresentative of typical production > activity), the more likely it is that you'll think "this is working". > > Assuming you mean to set up two MySQL servers each pointing at a > synchronised > DRBD storage volume on their local systems, the main thing I expect to go > wrong is data cached in memory, perhaps during complex updates. > > If instead you mean to have only one instance of MySQL running at any > given > time, and a failover involves stopping MySQL on the first node and then > starting it on the second, then sure, that will work, but it introduces a > (probably multi-second at the very least) delay during which no client > requests can be processed during the failover, whereas a replicated Galera > cluster (especially with something like ProxySQL in front of it) offers > almost > instantaneous switchover and therefore much reduced downtime in DB > availability. > > > More I know about MySQL more postgresql seems have better replication at > > least for me. > > So why not use Postgres? > > > Antony. > > -- > I don't know, maybe if we all waited then cosmic rays would write all our > software for us. Of course it might take a while. > > - Ron Minnich, Los Alamos National Laboratory > > Please reply to the > list; > please *don't* CC > me. > _______________________________________________ > Manage your subscription: > https://lists.clusterlabs.org/mailman/listinfo/users > > ClusterLabs home: https://www.clusterlabs.org/ >
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