Warning: option 'innodb_file_io_threads': signed value 1 adjusted to 4
/home/travis/server/bin/mariabackup based on MariaDB server 10.4.2-MariaDB Linux (x86_64) 
mariabackup: cd to /home/travis/logs/vardir/backup_0/
mariabackup: This target seems to be not prepared yet.
mariabackup: using the following InnoDB configuration for recovery:
mariabackup:   innodb_data_home_dir = .
mariabackup:   innodb_data_file_path = ibdata1:12M:autoextend
mariabackup:   innodb_log_group_home_dir = .
2019-01-10 06:21:55 0x7f353d131740 InnoDB: Using Linux native AIO
mariabackup: Starting InnoDB instance for recovery.
mariabackup: Using 104857600 bytes for buffer pool (set by --use-memory parameter)
2019-01-10  6:21:55 0 [Note] InnoDB: !!!!!!!! UNIV_DEBUG switched on !!!!!!!!!
2019-01-10  6:21:55 0 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2019-01-10  6:21:55 0 [Note] InnoDB: Uses event mutexes
2019-01-10  6:21:55 0 [Note] InnoDB: Compressed tables use zlib 1.2.8
2019-01-10  6:21:55 0 [Note] InnoDB: Number of pools: 1
2019-01-10  6:21:55 0 [Note] InnoDB: Using SSE2 crc32 instructions
/home/travis/server/bin/mariabackup: O_TMPFILE is not supported on /tmp (disabling future attempts)
2019-01-10  6:21:55 0 [Note] InnoDB: Initializing buffer pool, total size = 100M, instances = 1, chunk size = 100M
2019-01-10  6:21:55 0 [Note] InnoDB: Completed initialization of buffer pool
2019-01-10  6:21:55 0 [Note] InnoDB: If the mysqld execution user is authorized, page cleaner thread priority can be changed. See the man page of setpriority().
2019-01-10  6:21:55 0 [Note] InnoDB: Starting crash recovery from checkpoint LSN=139812
Last binlog file , position 0
190110 06:21:55 completed OK!