A misuse of caching technology (for example, saving huge database selection results in cache) will significantly increase web page generation time and server load.

Another risk lurks in the buildup of unused and outdated cache files. This may happen if the expired cache auto purge feature is not configured correctly on "Settings > System Settings > Cache Settings".

Caching any large data objects (over 1 MB) is not recommended. Instead, you have to optimize Bitrix Framework API calls and define more strict filters for database selection queries. It's good to occasionally check the size of the "/bitrix/cache" folder; delete expired cache using the system ("Settings > System Settings > Cache Settings") or operating system tools. Another way is to use "memcached" for cache management.

• Set the statistics summary debug mode. Perform the stress test using real-life amount of test data (thousands of catalog items, tens of thousands users etc.) and see the component and page cache size:

  

  You have to check all, or at least the most visited pages of your website. Remember that the proper amount of test data is of the essence, otherwise you may miss cache overflows.
• If using file cache, ensure that a means to control the number and size of cache files in "/bitrix/cache" exists (e.g. Nagios). If the cache mechanism implementation of some of your components is faulty, the file cache may inflate uncontrollably and you may well find a million files totaling to 100 GB after a year. Ensure a means to purge the file cache exists.