xtrabackup: recognized server arguments: --datadir=/var/lib/mysql xtrabackup: recognized client arguments: 230609 18:37:44 innobackupex: Starting the backup operation IMPORTANT: Please check that the backup run completes successfully. At the end of a successful backup run innobackupex prints "completed OK!". 230609 18:37:44 version_check Connecting to MySQL server with DSN 'dbi:mysql:;mysql_read_default_group=xtrabackup' as 'ser=root' (using password: YES). Failed to connect to MySQL server: DBI connect(';mysql_read_default_group=xtrabackup','ser=root',...) failed: Access denied for user 'ser=root'@'localhost' (using password: YES) at - line 1314. 230609 18:37:44 Connecting to MySQL server host: localhost, user: ser=root, password: set, port: not set, socket: not set Failed to connect to MySQL server: Access denied for user 'ser=root'@'localhost' (using password: YES).

这个错误提示显示在使用xtrabackup工具备份MySQL数据库时出现了连接MySQL服务器的错误，无法连接到MySQL服务器。

错误提示中指出连接MySQL服务器失败的原因是访问被拒绝，可能原因包括：

1. 用户名或密码错误。
2. MySQL服务器拒绝了该用户的连接请求。
3. 防火墙或网络设置阻止了MySQL服务器的访问。

您可以检查备份命令中MySQL服务器的用户名和密码是否正确，并确保该用户有足够的权限连接和备份MySQL服务器。如果用户信息正确，请检查MySQL服务器的日志以获取更多信息，或者检查网络和防火墙设置以确保MySQL服务器的访问被允许。