Proxy Backup - FAQ - MySQL iDataAgent
Can I verify the status of a proxy server before performing a backup?
Yes. You can verify the status of a proxy server before performing a backup. Type the following command in MySQL prompt to verify the status of the proxy server:
mysql> show slave status
The proxy server is online, if both the I/O and SQL threads show the status as YES.
What are the prerequisites for performing a proxy backup?
Before performing a proxy backup on the subclients of a master server instance, ensure the following:
- The Master and proxy servers should be installed and running.
- The MySQL iDataAgent should be installed on both the master and proxy servers.
- The Instances of both the master and proxy servers should be configured to perform the proxy backups.
- The subclient on the master server should be configured to use the proxy for backups.
- Verify whether the status of the Proxy server is Online or Offline.
How is a failover to source implemented during a proxy backup?
When you start a proxy backup on the subclient of a master server instance, the system will check for the status of the slave/proxy server. If both the I/O and SQL threads are in running state, the system will intimate the job manager to perform a backup on the proxy. If either of the threads are not in running state, then the system will report the proxy status as false to the Job Manager and indicates that this job has to fail-over to the source. The job will then switch to the source (master) server and starts the scan phase if it is a FULL backup. If it is an Incremental backup, it will start from the transaction log phase. Once a failover to source occurs, all the subsequent jobs will be performed on the source server itself until the next full backup cycle i.e., until the start of the next full backup job. The fail-over is initiated only if you select Use source if proxy is unavailable option in the subclient properties. See Enabling the Failover to Source if Proxy is Unavailable for step-by-step instructions.
The fail-over is initiated in the following circumstances:
- If the Proxy server is inaccessible. If the proxy server is unreachable, the job manager will initiate the backup on the master server.
- If the proxy server is not in running state. This is also considered as replication down and is indicated as a fail-over to the job manager.
Will the replication between the master and proxy servers continue when you restore a master server?
In a replication setup, the replication between the master and slaves can break as a result of restore to master server. Hence, it is a good practice to stop the replication process to slave before restoring a master server. After restoring a master server, make sure that the replication is online on the proxy server.
When you start the deletion of logs on master server, verify the status of the proxy server using show slave status command. The output of this command includes a Master_Log_File field. This field indicates the number of the current log file that the proxy server is reading on master. Any log files with the numbers less than this number are considered eligible for deletion. These logs are deleted after the backup.
If the master server is having the logs mysql_bin.000225, 226, 227… 234., and the current Master_Log_File=mysql_bin.000234 on proxy server, then the logs 225,226,227,228,229,230,231,232,233 are eligible for deletion on master.
What are the supported replication types?
The following table displays the support information of various replication types:
|Entire server replication|
|One master- one slave replication|
|Cascading master-slave replication (A slave itself acting as a master to another slave)|
|One master- multiple-slave replication|
|MySQL Cluster replication|
|Master to master replication|