← Back to team overview

maria-discuss team mailing list archive

Re: Galera cluster with asynchronous slave


On 04. juli 2014 10:44, erkan yanar wrote:
Ahoi Johnny,
Ahoi there :)

On Thu, Jul 03, 2014 at 02:16:26PM +0200, Johnny Antonsen wrote:
Got fatal error 1236 from master when reading data from binary log:
'Error: connecting slave requested to start from GTID 3-1-422, which
is not in the master's binlog'

And the Slave_IO_State shows that it's no longer in sync.

I have run SELECT @@GLOBAL.gtid_slave_pos; to check what the current
GTID for each node is, and they all return: 1-1-2145, however,
sometimes if I add a lot of data, that value is different on some
nodes, which is why I think the slave gets confused.
Using Galera there is no different Data on the nodes.

On the slave, when activating using_gtid=slave_pos, the following
gtid_IO_pos appear: 1-1-2464,2-3-420,3-1-422
Why are you using different domain-ids?

From what this documentation says, it is recommended to use different domain-ids

Here it says " In such setups, each active master must be configured with its own distinct replication domain ID, gtid_domain_id. The binlog will then in effect consists of multiple independent streams, one per active master. Within one replication domain, binlog order is always the same on every server."

And as I'm trying to run a slave from multiple masters, this relates to my current setup doesn't it?

 From what I have read, this should be somewhat correct, as the first
value is the server id. However, in the config I have specified that
node 1 has server id 1, node 2 has id 2 and so on, and that the same
goes for gtid_domain_id. Is this the correct setup or do the nodes
need to have the same server-id or gtid_domain_id?
The secound value is the server-id.
Ok, so that means that each value on the various servers in a galera clusters will be unique, like node 1 will have gtid 1-1-xxx and node 2 will have 1-2-xxx and so on? According to what you mention further up about domain id's being unique.

Surely there must be a good way to solve this? Is the system not
built to handle an asynchronous slave replicating from one random

I don't know what you are doing.
All I can say Im doing also MariaDB GTID slaves and it works.
Even Im not sure if domain-id matters - I haven't set them at all - be sure
to have log_slave_updates and bin_log enabled.
What I'm trying to do is actually pretty simple when you think about it. I have three servers running mariadb and being in a galera cluster. Each server has haproxy and keepalived running to move a virtual ip over and haproxy for checking if the actual service is up and running. On another site I have a mariadb server running with master set to the virtual ip assigned by keepalived. All this server has to do is replicate data from the mysql server it reaches once it connects.

This works fine when it reaches the first server, but once it jumps to the next server I get a message saying that the GTID is not in the current binlog. The using_gtid value is set to slave_pos.

log_slave_updates is enabled on all three servers running galera, and so is binlog using ROW.

Hope this explains a little more on what I'm trying to achieve.



Follow ups