innodb_file_format Barracuda I have a couple questions for those more familiar.  Most of my instances have been running Antelope despite having support for Barracuda.

I was looking to play around with some compresses innodb tables.  My understanding is this is only available under the Barracuda format.


I see innodb_file_format is dynamic so I can just switch over with out a bounce.  Are there any implications of doing this I should be aware of.  All I can tell is that means new tables or subsequently altered will be created with that format.  Is this all correct?
I was hoping to have to not go through and convert all my tables.  Is is kosher to have antelope and barracude tables coexisting in the same tablespace? Even if it works are there any gotcha's to look out for?


From what I've read and gathered from my tests the answers are: Yes. Yes. I'm not sure.

Update

I've been running w/ some Dynamic and some Compressed tables in various instances since this post with out issue.  Further I neglected to read http://dev.mysql.com/doc/refman/5.5/en/innodb-file-format-identifying.html  at the time.  


  After you enable a given innodb_file_format, this change applies only
  to newly created tables rather than existing ones. If you do create a
  new table, the tablespace containing the table is tagged with the
  “earliest” or “simplest” file format that is required for the table's
  features. For example, if you enable file format Barracuda, and create
  a new table that is not compressed and does not use
  ROW_FORMAT=DYNAMIC, the new tablespace that contains the table is
  tagged as using file format Antelope.


So tables will be created as Antelope even if you allow Barracuda.  The mixing is unavoidable unless you specify every table as row_format dynamic or a compressed table.  

There is no indication you should do a complete dump and reload when introducing your first Barracuda table (such as is recommended when upgrading major versions of mysql)
So I'm answering this question almost 4 years late:


InnoDB file formats were conceived at a time when InnoDB was independent of the MySQL Server (for example: MySQL 5.1 could run two different versions of InnoDB).
The reason why you would not want to run Barracuda (in 2012) is that it could reduce flexibility in downgrading MySQL (i.e. after a failed upgrade, you want to move back to a version that can not read a newer format).  i.e. there should be no technical reasons why Antelope is better.
In MySQL 5.7 the innodb_file_format option was deprecated.  Since MySQL and InnoDB are no longer independent, and thus InnoDB can use the MySQL rules of upgrades and what backwards compatibility is required.  No confusing setting required!
In MySQL 5.7, the default switched to Barracuda/DYNAMIC.  Since all currently supported releases of MySQL can read this format, it is safe to move away from Antelope and still offer downgrade.
On a MySQL 5.7 server, Antelope tables will be upgraded to Barracuda/DYNAMIC on the next table rebuild (OPTIMIZE TABLE etc).  That is unless they were specifically created with ROW_FORMAT=oldrowformat.
In MySQL 8.0, the option innodb_file_format is removed.




MySQL 5.7 also introduces the option innodb_default_row_format, which defaults to DYNAMIC.  This addresses the point in your update.