[root@instance-atfaffll ~]# xtrabackup --defaults-file=/etc/my.cnf --host=localhost --user=root --password=123456 --port=3306 --backup --target-dir=/xtrabackupinc --incremental-basedir=/xtrabackupfull/xtrabackup: recognized server arguments: --datadir=/data/mysql/data --server-id=6 --log_bin=/data/binlog/mysql-bin --innodb_flush_method=O_DIRECT
xtrabackup: recognized client arguments: --socket=/tmp/mysql.sock --host=localhost --user=root --password=* --port=3306 --backup=1 --target-dir=/xtrabackupinc --incremental-basedir=/xtrabackupfull/
xtrabackup version 8.0.25-17 based on MySQL server 8.0.25 Linux (x86_64) (revision id: d27028b)
xtrabackup: Error: cannot open /xtrabackupfull//xtrabackup_checkpoints
xtrabackup: error: failed to read metadata from /xtrabackupfull//xtrabackup_checkpoints
如果全备目录是空的，就会报这个错，也就是说全备完成后不要删除全备数据目录，需要恢复的时候再考虑备份目录后再执行清空操作，因为全备后你压缩备份目录后立马清空，那么增量备份就失去了根基目录base