MySQL Enterprise Backup User's Guide (Version 4.1.5)
For Linux and other Unix-like platforms:
mysqlbackup does not record file ownership or
permissions of the files that are backed up. To ensure no file
permission issues prevent a server to be backed up, restored,
and restarted successfully, it is highly recommended
that you run mysqlbackup with the same OS user who runs the
MySQL server (typically mysql). If
that is not possible, pay attention to the following guidelines:
For backups, mysqlbackup should be run by
a user that can read all the server files and directories
and can execute all server directories. To satisfy that
requirement, the OS user that runs
mysqlbackup should, for example, have the
group owner of the server files and directories (typically
mysql) as its primary group or secondary
group.
For restores, unless mysqlbackup is run
by the same user that runs the server, it can be very hard
to ensure that the server has access to all the restored
server files and folders, especially in the case of an
online restore, where the server must be able to access the
files immediately after they are restored. For an offline
restore, you might need to, for example, set a
umask to the user before the restore and
adjust the permissions of the restored files and folders
using a series of chmod and
chown commands, so that the original
permissions for the backed-up files and folders are
reproduced.