I am controlling an internet site that's constructed from the floor-up in PHP and uses AJAX extensively to load pages inside the site.

Presently, the 'admin' interface I produced stores the HTML for every page, the page's title, custom CSS for your page, plus some other characteristics in JSON inside a file directory (e.g. example.com/hi might have its data saved in example.com/json/hi/data.json).

Is more effective (performance-smart) than utilizing a database (MySQL) to keep all the content?

EDIT: I realize that direct filesystem access is much more efficient than utilizing a database, but I am not only obtaining the items in personal files I have to use json_decode to parse the JSON into an itemOrvariety first to utilize it. May be the performance hit from that minimal?

Thad is dependent on which you utilize that data for.

Should you only serve 'static' files, with almost exactly the same data constantly, then even static HTML files are suggested for chaching.

If, however, you process data and display it in multiple forms (searches, custom statistics, etc) then its much easier to store it in certain type of DB

Your manner does not sounds very bad, actually I made use of a not-so-far solution before and it works very good. However, you might consider more effective storage the moment your admin will grow or the necessity to separate things arises. Since, you will find two ways :

SQL : using relationnal database like Postgre or MySQL

No-SQL : which appears to become much more of your interest, here's why.

Thinking about you are using ajax for communication and json for storage, there's MongoDB. A no sql method of storage which use json syntax for querying. There even is definitely an Interactive Tutorial for this !

If this involves performances, nobody sounds to become faster. Both engine usually designed in C or C++, that's, for the best performances. Nonetheless, for any structure as easy as you describe, there is no faster way than direct file access.