MariaDB Galera stops working without network connectivity

[Ashraful Islam]

Hi, 

I am running MariaDB Galera cluster whose using mariaDB and 3 nodes(node A, node B, node C). My nodes are placed locally in our office.

My problem is if node A/B/C lost network connection, it also lost it's working ability.

Say a application is connected to node A, then node A lost network connectivity, so when someone tries to read/write data on node A using physical access,say CLI, it doesn't work. 

It's showing,ERROR 1047 WSREP has not yet prepared node for application use

I want to use node A/B/C offline as well. When they get back the network connection, it will automatically replicate offline data to the connected nodes.

Thanks in advance,

Nixon

[Lammert Bies]

The concept of Galera cluster doesn't allow to use disconnected nodes off-line in write mode and resynchronize them with the cluster at a later moment. One reason is that if on two separated nodes records are inserted with the same value as primary key or unique index, duplicate issues will occur when merging them. Software alone cannot decide in such a situation which record is valid and which one should be discarded.

An option might be to use a proxy solution between the client and the servers which automatically reconnects a client to a synchronized node in the cluster when the cluster node the client was connected to fails. Haproxy for example could do this job.