HowTo: Migrate / Move MySQL Database And Users To New Server

Posted on in Categories MySQL last updated June 22, 2012

I already wrote about how to move or migrate user accounts from old Linux / UNIX server to a new server including mails and home directories. However, in reality you also need to move MySQL database which may host your blog, forum or just your data stored in MySQL database. The mysqldump command will only export the data and the table structure but it will not include a users grants and privileges. The main function of the MySQL privilege system (which is stored in mysql.user table) is to authenticate a user who connects from a given host and to associate that user with privileges on a database such as SELECT, INSERT, UPDATE, and DELETE.

Linux HugeTLBfs: Improve MySQL Database Application Performance

Posted on in Categories CentOS, Hardware, High performance computing, Howto, MySQL, RedHat/Fedora Linux last updated May 20, 2009

Applications that perform a lot of memory accesses (several GBs) may obtain performance improvements by using large pages due to reduced Translation Lookaside Buffer (TLB) misses. HugeTLBfs is memory management feature offered in Linux kernel, which is valuable for applications that use a large virtual address space. It is especially useful for database applications such as MySQL, Oracle and others. Other server software(s) that uses the prefork or similar (e.g. Apache web server) model will also benefit.

The CPU’s Translation Lookaside Buffer (TLB) is a small cache used for storing virtual-to-physical mapping information. By using the TLB, a translation can be performed without referencing the in-memory page table entry that maps the virtual address. However, to keep translations as fast as possible, the TLB is usually small. It is not uncommon for large memory applications to exceed the mapping capacity of the TLB. Users can use the huge page support in Linux kernel by either using the mmap system call or standard SYSv shared memory system calls (shmget, shmat).