target-dir option is being ignored

when i give the follwoing command
xtrabackup --user=xbackup --password=backup -S /mysql/gopz/mysql-5.7.22-linux-glibc2.12-x86_64/3306.sock --backup -target-dir=/mysql/backup/ --datadir=/mysql/gopz/data1

the backup is happening successfully the backup files are bring generated at a completely different location (not the one specified but instead backup files are being generated in /dbdata/mysql/xtrabackup_backupfiles/xtrabackup_backupfiles ,can anyone help me understand what im doing wrong

180815 15:31:40 [00] Writing /dbdata/mysql/xtrabackup_backupfiles/xtrabackup_backupfiles/backup-my.cnf
180815 15:31:40 [00] …done
180815 15:31:40 [00] Writing /dbdata/mysql/xtrabackup_backupfiles/xtrabackup_backupfiles/xtrabackup_info
180815 15:31:40 [00] …done
xtrabackup: Transaction log of lsn (2597071) to (2597080) was copied.

180815 15:31:40 completed OK!