cat /data/maria10.3/innobackup.backup.log
190217 15:11:28 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!".

190217 15:11:28 Connecting to MySQL server host: localhost, user: xxxxx, password: set, port: xxx6, socket: /tmp/mysqlxxx5.sock
Using server version 10.3.12-MariaDB-log
--innobackupex based on MariaDB server 10.3.12-MariaDB Linux (x86_64) 
mariabackup: uses posix_fadvise().
mariabackup: cd to /data/maria10.3/
Loading encryption plugin
	 Encryption plugin parameter :  '--aws_key_management_key_spec=AES_xxx'
	 Encryption plugin parameter :  '--aws_key_management_log_level=Info'
	 Encryption plugin parameter :  '--aws_key_management_master_key_id=alias/xx'
	 Encryption plugin parameter :  '--aws_key_management_region=xx-xxxx-1'
	 Encryption plugin parameter :  '--aws_key_management_request_timeout=0'
	 Encryption plugin parameter :  '--aws_key_management_rotate_key=-1'
mariabackup: open files limit requested 0, set to 1048576
mariabackup: using the following InnoDB configuration:
mariabackup:   innodb_data_home_dir = 
mariabackup:   innodb_data_file_path = ibdata1:12M:autoextend
mariabackup:   innodb_log_group_home_dir = ./
2019-02-17 15:11:28 0x7fd695f90780 InnoDB: Using Linux native AIO
2019-02-17 15:11:28 0 [Note] InnoDB: Number of pools: 1
--innobackupex: AWS KMS plugin: loaded key 1, version 1, key length 128 bit
mariabackup: Generating a list of tablespaces
2019-02-17 15:11:28 0 [Warning] InnoDB: Allocated tablespace ID 1 for mysql/innodb_table_stats, old maximum was 0
190217 15:11:28 >> log scanned up to (1724229)
190217 15:11:28 [01] Streaming ibdata1
--innobackupex: Error writing file 'UNKNOWN' (Errcode: 32 "Broken pipe")
xb_stream_write_data() failed.
--innobackupex: Error writing file 'UNKNOWN' (Errcode: 32 "Broken pipe")
[01] mariabackup: Error: xtrabackup_copy_datafile() failed.
[01] mariabackup: Error: failed to copy datafile.