![]() They also need to know, at any time, which of the instances is the PRIMARY. In order for applications to handle failover, they need to be aware of the topology of the InnoDB cluster. If that instance becomes unreachable for any reason (like a system crash), one of the remaining two instances automatically takes over its place and becomes the new PRIMARY. Only the instance marked R/W can execute transactions that update the database. RECOVERING means that the instance is receiving updates from the seed instance and should eventually switch to ONLINE.Īnother point to note is that one of the instances (the PRIMARY) is marked R/W (read/writable), while the other two are marked R/O (read only). The status field for each instance should show either ONLINE or RECOVERING. This command queries the current status of the InnoDB cluster and produces a short report. Any transactions that were executed in the seed instance will be re-executed in each added replica.Īdd two blank instances to the InnoDB cluster: just the metadata schema and internal accounts) and have binary logging enabled from the beginning, there’s very little that new replicas need to catch up with. Otherwise, Group Replication will perform a sync automatically, re-executing all transactions from the seed, as long as they’re in the MySQL binary log. Since the seed instance in this example has little to no data (ie. The MySQL Shell will soon also provide a mechanism to perform that step with minimal effort. If the amount of pre-existing data in the seed instance is very large, you may want to clone it or copy that data through a fast method beforehand. Usually, whenever a new instance is added to a replica set in a cluster, they will be completely empty and need to catch up to the current state of the seed instance. We use the blank sandbox instances that we created earlier. Now, you need to add replicas to the InnoDB cluster. If some change requires the MySQL Server to be restarted, you must do it manually whenever is convenient. The command ensures that the settings are correct and if not, it reconfigures the server. Sandbox instances are pre-configured to work with replication, but if you use a pre-existing instance, it’s possible that some configuration options might not be set correctly. The system will create and manage single use accounts with minimal privileges internally for you. ![]() This allows a secure by default deployment without sacrificing ease-of-use. This key is needed to manage the InnoDB cluster and you will also need it later to bootstrap MySQL Router instances for use with the cluster. You will prompted for a master administrative key. ![]() ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |