According to this link, I executed this command to backup my database:
xtrabackup --backup --databases='database' --target-dir=/home/user/backups --datadir=/var/lib/mysql/
But I get the following error:
160520 02:00:54 version_check Done.
160520 02:00:54 Connecting to MySQL server host: localhost, user: root, password: set, port: 0, socket: /var/lib/mysql/mysql.sock
Using server version 5.5.44-MariaDB
xtrabackup version 2.4.2 based on MySQL server 5.7.11 Linux (x86_64) (revision id: 8e86a84)
xtrabackup: uses posix_fadvise().
xtrabackup: cd to /var/lib/mysql/
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:autoextend
xtrabackup: innodb_log_group_home_dir = .
xtrabackup: innodb_log_files_in_group = 2
xtrabackup: innodb_log_file_size = 5242880
InnoDB: Number of pools: 1
InnoDB: Operating system error number 13 in a file operation.
InnoDB: The error means mysqld does not have the access rights to the directory.
I solved it by running the same command with sudo, the problem is that the backup directory gets created as root so my user doesn't have access to that directory so I always have to change the ownership recursively for that directory so I can be able to read it. This method isn't pretty efficient to me.
The xtrabackup tool runs as the user invoking it and that user must be able to read the database files which are normally owned by mysql:mysql and mode 660.
An easy fix is usually to add the user to the mysql group, for example:
useradd -G mysql yves
Then logout and re-open the session, it should work.