Elena Stepanova added a comment - 2015-04-28 15:25 Hi, Please note that ignore_db_dirs refer to the directory name, as opposed to the database name, and the difference is important here. From your output, it looks like you previously ran create database `lost+found` , and not mkdir <datadir>/lost+found . If you look into your datadir, you'll see that the existing directory is not lost+found , it's something like lost@002bfound . It gets converted back when you run show databases . It works the same way in 5.5.38 and 10.0, see output from 5.5.38 below. MariaDB [test]> select @@version; + ----------------+ | @@version | + ----------------+ | 5.5.38-MariaDB | + ----------------+ 1 row in set (0.00 sec)   MariaDB [test]> select @@ignore_db_dirs; + ------------------+ | @@ignore_db_dirs | + ------------------+ | lost+found | + ------------------+ 1 row in set (0.00 sec)   MariaDB [test]> select @@datadir; + --------------------------------------------------+ | @@datadir | + --------------------------------------------------+ | /data/releases/mariadb-5.5.38-linux-x86_64/data/ | + --------------------------------------------------+ 1 row in set (0.00 sec) MariaDB [test]> system ls /data/releases/mariadb-5.5.38-linux-x86_64/data/ aria_log.00000001 aria_log_control ibdata1 ib_logfile0 ib_logfile1 mysql performance_schema test wheezy-64.err wheezy-64.pid   MariaDB [test]> system mkdir /data/releases/mariadb-5.5.38-linux-x86_64/data/lost+found   MariaDB [test]> system ls /data/releases/mariadb-5.5.38-linux-x86_64/data/ aria_log.00000001 aria_log_control ibdata1 ib_logfile0 ib_logfile1 lost+found mysql performance_schema test wheezy-64.err wheezy-64.pid   MariaDB [test]> show databases like "lost+found" ; Empty set (0.00 sec) MariaDB [test]> create database `lost+found`; Query OK, 1 row affected (0.00 sec)   MariaDB [test]> system ls /data/releases/mariadb-5.5.38-linux-x86_64/data/ aria_log.00000001 ibdata1 ib_logfile1 lost+found performance_schema wheezy-64.err aria_log_control ib_logfile0 lost@002bfound mysql test wheezy-64.pid   MariaDB [test]> show databases like "lost+found" ; + -----------------------+ | Database (lost+found) | + -----------------------+ | lost+found | + -----------------------+ 1 row in set (0.00 sec)

Ainsley added a comment - 2015-04-29 09:29 Thank you, you were correct. 'lost@002bfound' was created by a raw data directory copy from one data dir to another.

Elena Stepanova added a comment - 2015-04-29 11:00 In this case it works as expected, closing a 'Not a bug'. Please feel free to comment if you disagree.

drupal_user added a comment - 2015-12-21 15:48 There seems to be a bug, though. I mounted /var/lib/mysql on a separate partition before installing mysql-server. After installing: I have /var/lib/mysql mounted as its own ext4 filesystem. By default, the filesystem has a directory at its root named lost+found, which is used for cleanup during bad filesystem checks. When i install mysql-server, it mangles this directory (which doesn't really belong to it) into "lost@002bfound", and changes ownership on it to mysql:mysql: ls -l /var/lib/mysql/ rw-r r - 1 root root 0 Nov 8 11:34 debian-5.1.flag rw-rw --- 1 mysql mysql 10485760 Nov 8 11:35 ibdata1 rw-rw --- 1 mysql mysql 5242880 Nov 8 11:35 ib_logfile0 rw-rw --- 1 mysql mysql 5242880 Nov 8 11:34 ib_logfile1 drwx------ 2 mysql mysql 4096 Nov 8 11:35 lost@002bfound drwx------ 2 mysql root 4096 Nov 8 11:35 mysql rw ------ 1 root root 6 Nov 8 11:35 mysql_upgrade_info 0 stylus:~# Note the wrong permission lost@002bfound directory. It also now has a db.opt file inside it. I'm not sure how to repair this? What should I do with the db.opt file? I already looked at: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=608938