Disk-based database caching: Disadvantages?

Question

I'm running a database-backed web site on shared hosting that occasionally gets swarmed after a mention on a link sharing site.

Because of how much load the first couple of traffic surges put on the database, I have implemented file-based caching.

When a query runs, I just serialize the resultset object and save it to a file. I have a sub-directory structure in the cache directory that keeps thousands of files from ending up in the same directory. Next time I have to run the same query, I just pull the object out of the file instead.

It's been working pretty well so far. But I'm worried that I am overlooking something, and possibly asking for trouble if there is a higher level of traffic than I've previously enjoyed. Or maybe there's just an easier way to do this?

Please poke some holes in this for me? Thanks!

Answer 1

Ideally. cache in memory to remove disk access. Have a look at something like memcached

Answer 2

Since you're on shared hosting, you should do some throttling (google "Throttling your web server (Oct 00)" for ideas).

A related interesting read (which also mentions Stonehenge::Throttle) is Building a Large-Scale E-commerce site with Apache and mod_perl http://perl.apache.org/docs/tutorials/apps/scale%5Fetoys/etoys.html