backup may show corruption with custom innodb_data_file_path

170506 09:06:04 [01] Copying ./ibdata1 to /dev/shm/__var0/var1/backup/full/ibdata1

170506 09:06:05 [01]        ...done

170506 09:06:05 [01] Copying ./ibdata2 to /dev/shm/__var0/var1/backup/full/ibdata2

InnoDB: Checksum fields zero but page is not empty.

[01] xtrabackup: Database page corruption detected at page 0, retrying...

InnoDB: Checksum fields zero but page is not empty.

[01] xtrabackup: Database page corruption detected at page 0, retrying...

bash: ===> 10.1.23/bin/mariabackup --defaults-file=/dev/shm/__var0/var1/my.cnf --backup --target-dir=/dev/shm/__var0/var1/backup/

170506 09:13:48 Connecting to MySQL server host: localhost, user: root, password: not set, port: not set, socket: /dev/shm/__var0/tmp/mysql.sock.X8lno8

Using server version 10.1.23-MariaDB

10.1.23/bin/mariabackup based on MariaDB server 10.1.23-MariaDB Linux (x86_64) 

xtrabackup: uses posix_fadvise().

xtrabackup: cd to /dev/shm/__var0/var1/data

xtrabackup: open files limit requested 0, set to 1024

xtrabackup: using the following InnoDB configuration:

xtrabackup:   innodb_data_home_dir = ./

xtrabackup:   innodb_data_file_path = ibdata1:10M;ibdata2:5M:autoextend

xtrabackup:   innodb_log_group_home_dir = ./

xtrabackup:   innodb_log_files_in_group = 2

xtrabackup:   innodb_log_file_size = 50331648

170506 09:13:48 >> log scanned up to (1616829)

xtrabackup: Generating a list of tablespaces

170506 09:13:49 [01] Copying ./ibdata1 to /dev/shm/__var0/var1/backup/ibdata1

170506 09:13:49 [01]        ...done

170506 09:13:49 [01] Copying ./ibdata2 to /dev/shm/__var0/var1/backup/ibdata2

InnoDB: Checksum fields zero but page is not empty.

[01] xtrabackup: Database page corruption detected at page 0, retrying...

InnoDB: Checksum fields zero but page is not empty.

[01] xtrabackup: Database page corruption detected at page 0, retrying...

InnoDB: Checksum fields zero but page is not empty.

[01] xtrabackup: Database page corruption detected at page 0, retrying...

InnoDB: Checksum fields zero but page is not empty.

[01] xtrabackup: Database page corruption detected at page 0, retrying...

InnoDB: Checksum fields zero but page is not empty.

[01] xtrabackup: Database page corruption detected at page 0, retrying...

InnoDB: Checksum fields zero but page is not empty.

[01] xtrabackup: Database page corruption detected at page 0, retrying...

InnoDB: Checksum fields zero but page is not empty.

[01] xtrabackup: Database page corruption detected at page 0, retrying...

InnoDB: Checksum fields zero but page is not empty.

[01] xtrabackup: Database page corruption detected at page 0, retrying...

170506 09:13:49 >> log scanned up to (1616829)

InnoDB: Checksum fields zero but page is not empty.

[01] xtrabackup: Database page corruption detected at page 0, retrying...

InnoDB: Checksum fields zero but page is not empty.

[01] xtrabackup: Error: failed to read page after 10 retries. File ./ibdata2 seems to be corrupted.

[01] xtrabackup: Error: xtrabackup_copy_datafile() failed.

[01] xtrabackup: Error: failed to copy datafile.

2017-05-06 09:13:49: bash: ===> mariabackup failed with exit code 1