Clearing machine cache

There isn't directly, no. However, you can do something clever with CACHE_REQUEST, CACHE::age, and CACHE::expire. I can't code this up for you, but will describe how to do it. Basically, when you clear the cache at a certain time, any documents that were cached before that time get expired. You can do that in iRules, just not all at once. You would have some variable which contains a timestamp which is the last time you cleared the cache, and for each request you just check if the age of the document is longer than "time since cache was cleared" (which you do with CACHE::age, the clock command, and some math), and call CACHE::expire if it is. Then you need some way of updating that variable whenever you want to clear the cache. You probably want to store the variable in the session table, also.