Starting at version MySQL5.6+ by default innodb_file_per_table is enabled and all data is stored in separate tablespaces.

It provides some advantages. I will highlight some of them:

• You can reclaim disk space when truncating or dropping a table stored in a file-per-table tablespace. Truncating or dropping tables stored in the shared system tablespace creates free space internally in the system tablespace data files (ibdata files) which can only be used for new InnoDB data.
• You can store specific tables on separate storage devices, for I/O optimization, space management, or backup purposes. …

I was recently asked a question by mail about MySQL Lossless Semi-Synchronous Replication. As I think the answer could benefit many people, I am answering it in a blog post. The answer brings us to the internals of transaction committing, of semi-synchronous replication, of MySQL (server) crash recovery, and of storage engine (InnoDB) crash recovery. I am also debunking some misconceptions that I have often seen and heard repeated by many. Let’s start by stating one of those misconceptions.

One of those misconceptions is the following (this is NOT true): semi-synchronous enabled slaves are always the most up-to-date slaves (again, this is NOT true). If you hear it yourself, then please call people out on it to avoid this spreading more. Even if some slaves have semi-synchronous replication disabled (I will use semi-sync for …