While we do have many blog posts on replication on our blog, such as on replication being single-threaded, on semi-synchronous replication or on estimating replication capacity, I don’t think we have one that covers the very basics of how MySQL replication really works on the high level. Or it’s been so long ago I can’t [...]
With the recent release of Percona XtraDB Cluster, I am increasingly being asked about MySQL’s semi-synchronous replication. I find that there are often a number of misconceptions about how semi-synchronous replication really works. I think it is very important to understand what guarantees you actually get with semi-synchronous replication, and what you don’t get. The [...]
I went to MongoSF today – quite an event, and I hope to have a chance to write more about it. This post is about one replication problem and how MongoDB solves it. If you’re using MySQL Replication when your master goes down it is possible for some writes to be executed on the master, [...]
One question which comes up very often is when one should use SAN with MySQL, which is especially popular among people got used to Oracle or other Enterprise database systems which are quite commonly deployed on SAN. My question in such case is always what exactly are you trying to get by using SAN ?
Running MySQL slave is quite common and regular task which we do every day, taking backups from slave is often recommended solution. However the current state of MySQL replication makes restoring slave a bit tricky (if possible at all). The main problem is that InnoDB transaction state and replication state are not synchronized. If we [...]
The problem with broken group commit was discusses many times, bug report was reported 3.5Â years ago and still not fixed in MySQLÂ 5.0/5.1 (and most likely will not be in MySQLÂ 5.1). Although the rough truth is this bug is very hard (if possible) to fix properly. In short words if you enable replication (log-bin) on server [...]
If someone asks me about MySQL Backup advice my first question would be if they have LVM installed or have some systems with similar features set for other operation systems. Veritas File System can do it for Solaris. Most SAN systems would work as well. What is really needed is ability to create atomic snapshot [...]
MySQL is known for its stability but as any other application it has bugs so it may crash sometime. Also operation system may be flawed, hardware has problems or simply power can go down which all mean similar things – MySQL Shutdown is unexpected and there could be various inconsistences. And this is not only [...]