What does the MySQL Query cache Hitrate % value respesent?

Question

Using MySQL Workbench I am looking at the Admin view for two servers I run.

Both servers have a similar bandwidth

On one server there is just one site it has a Query Cache Hit Rate of 15%

The other server has over 100 sites and 88 databases and has a Query Cache Hit Rate of 70%

I'm in the middle of learning about how best to optimise and increase the performance of these MySQL servers and can't find anything about what these values mean, what's good or bad and how they can be improved.

(I've searched a lot, but guess I haven't searched with the right terms)

Answer 1

From here:

The hit rate indicates the ratio of queries that were cached and queries that were not cached.

A high percentage certainly is an indication for an optimized setup, but there are other factors to be taken into care, too.