I have a Truecrypt partition, and I would like to create a mysql database on it, but I need to mount as a mysql user and mysql group, otherwise I can't create new tables. How can I mount this Truecrypt to belong to mysql user and mysql group?
I assume you're running Linux?
There seems to be a "--fs-options" flag, where you can specify the user and group of the truecrypt process.
Something like this might do it:
truecrypt --fs-options=users,uid=<uid of mysql user>,gid=<gid of mysql group>
Reference: https://wiki.archlinux.org/index.php/TrueCrypt#Method_1_.28Add_a_truecrypt_group.29