Shulou(Shulou.com)06/01 Report--

# Galera Cluster Features

There is no delay between clusters and replication is synchronized. While master-slave master-slave asynchronous replication, there is a delay.

Active-active is multi-master, and the servers in the cluster are all written at the same time, and the feedback will not be completed until all the databases in the cluster are written, so there is no data loss.

Cluster nodes fail over automatically, and if a single node in the cluster fails, the failed node will be cleared automatically.

Expansion is convenient, as long as the new node is added to the cluster, the new node automatically replicates data.

# Galera Cluster principle

# data consistency is mainly ensured through the galera plug-in. The process of data replication is verifiable replication. The principle is as follows:

# parsing

# the client requests update to update the data. After a server in the galera cluster receives the request, the local process reports that the OK,client will submit the data that needs to be changed by commit. After server receives the submitted transaction, all changes to the data will be collected by write-set and sent to other nodes. Write-set authenticates certification before each node executes. If the authentication is passed, the node applies write-set to record the change data; if the authentication fails, the node discards discard and write-set, and other nodes roll back the rollback transaction.

# Building Galera clusters

# Environment: Centos7

# Database version: 10.1.16-MariaDB

# # Environment preparation

# () modify the local host file, / etc/hosts

[root@js-test-1 ~] # cat / etc/hosts...10.10.86.43 galera01 10.10.86.44 galera0210.10.86.45 galera03...

# () modify the firewall & disable selinux

# () adjust firewall, galera cluster cluster communication principle

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