Why Cannot Standby Read Replicas on Some Other Clouds Be Used as the Source Database?

For incremental or full+incremental DRS tasks, standby read replicas on some other clouds cannot be used as the source database. DRS incremental migration reads the original incremental log data (for example, MySQL Binlog data) of the source database and parses and converts the data.

Take the Binlog data of MySQL as an example. The Binlog data in the standby read replicas on some other cloud MySQL is incomplete. As a result, DRS cannot perform incremental data synchronization. You can use mysqlbinlog to download and confirm the integrity of the Binlog data.

Run the following command to download Binlogs. Note that this command downloads all logs following the $binlogLogName file. If you only need to check the integrity of the Binlog data, you can select a Binlog to download.

mysqlbinlog --no-defaults -h$sourceHost -u$sourceUsername -P$sourcePort -p$sourcePassword --raw --read-from-remote-server $binlogLogName --to-last-log

Run the following command to view the Binlog data.

mysqlbinlog --base64-output=decode-rows -v $binlogLogName

• Complete Binlog data