Understanding barrier on Linux

It is known that massive write operations in Firebird databases (like updates affecting thousands or millions of records) had become much slower in more recent Linux servers. After investigation, I found this to be related with the fact that most recent distros brings the barrier parameter of the filesystem activated.

Unfortunately, I wasn’t able to solve this “problem” completely, without opening a door for corruption. The slow down when barrier is enabled can be minimized a lot if the database is configured with forced writes OFF, but this also may lead into corruption if something bad happens to the server.

Anyway, the purpose of this post is to share an article that helps to understand how barrier works and why it slow down such kind of operations.