Is it possible under normal circumstances to use the built in utf8 converter in the 4.0 upgrade script when upgrading from 3.4.6 to 4.0 on a medium sized community database with more than million posts?
The old pre 3.x quotes have been fixed on a forum I help to administrate using quote fix script, but there is some fixed quotes that are displaying the post snapback link without the image like this:
Is there a chance that rebuilding post content would fix this?
You don't need to increase the innodb bufffer pool size if you have no use for it, and I don't thinks it's necessary to remove the innodb database. Removing it would just help with mysql server manintenance and server backup I think.
If you follow any mysql tuning related advice in this topic now, I think you should run mysqltuner again within 6-12 hours just to make sure that changed configuration is not making the server perform worse.
When 24-48 hours have passed, you should run mysqltuner again and post the output in this topic.
You should perhaps use another tool like mysqlreport and read the guide.
table_cache (deprecated variable)
The default value for your version of MySQL is 400. I'm not sure if you can safely start with high value like 5000, or you should start with some lower value and increase it slowly in 2 or 3 steps and start with this:
It's probably not needed for your OS.