Comment 5 for bug 1376597

Something is wrong in former too, this is the log from SST:

141002 13:42:08 innobackupex: Starting ibbackup with command: xtrabackup --defaults-file="/etc/mysql/my.cnf" --defaults-group="mysqld" --backup --suspend-at-end --target-dir=/tmp/tmp.MUwYvJ7cQk --tmpdir=/tmp/tmp.MUwYvJ7cQk --extra-lsndir='/tmp/tmp.MUwYvJ7cQk' --stream=xbstream
innobackupex: Waiting for ibbackup (pid=19683) to suspend
innobackupex: Suspend file '/tmp/tmp.MUwYvJ7cQk/xtrabackup_suspended_2'

xtrabackup version 2.2.4 based on MySQL server 5.6.17 Linux (x86_64) (revision id: )
xtrabackup: uses posix_fadvise().
xtrabackup: cd to
xtrabackup: open files limit requested 65535, set to 65535
xtrabackup: using the following InnoDB configuration:
xtrabackup: innodb_data_home_dir = /var/lib/mysql
xtrabackup: innodb_data_file_path = ibdata1:10M:autoextend
xtrabackup: innodb_log_group_home_dir = /var/lib/mysql
xtrabackup: innodb_log_files_in_group = 2
xtrabackup: innodb_log_file_size = 50331648
xtrabackup: using O_DIRECT
>> log scanned up to (47464191)
2014-10-02 13:42:09 7f800c053720 InnoDB: Operating system error number 13 in a file operation.
InnoDB: The error means mysqld does not have the access rights to
InnoDB: the directory.
innobackupex: Error: The xtrabackup child process has died at /usr//bin/innobackupex line 2679.

innobackupex is not passing the default datadir to xtrabackup, so xtrabackup fails without a message while tries to copy contents from server storage (what you are checking now).