Frontend slowdown, freezes and errors

[masual]

After running 411 for a few weeks we are starting to experience some performance issues on the frontend. It takes too long to load the different pages and sometimes it completely freezes. The number of generated alerts is quite low (about 3000). Sometimes it gives the following error:

Error: Load timeout for modules: text!data_json_unnormalized2,text!data_json
http://requirejs.org/docs/errors.html#timeout require.js:7:1016
makeError http://172.16.4.200:30020/dist/js/libs/require.js:7
l http://172.16.4.200:30020/dist/js/libs/require.js:7
y http://172.16.4.200:30020/dist/js/libs/require.js:7

And also:

Error: Target db: SQLSTATE[HY000]: General error: 5 database is locked

We would appreciate any help you can provide us to debug the problem.

Regards