Where is my fragment cache?

I have been tearing my hair out trying to locate my fragment cache
files. For some reason they have recently disappeared. Let me explain.

I am using:
Rails 2.3.4
Ruby 1.8.7
Ubuntu 9.04

I have set my cache to file_store with:
config.cache_store = :file_store, "#{RAILS_ROOT}/tmp/cache"

Checking it in console confirms this:
ActionController::Base.cache_store
=> #<ActiveSupport::Cache::FileStore:0xb6fc045c
@cache_path="/home/zac/apps/app_name/trunk/tmp/cache">

However, and frustratingly, I am now seeing any cache files in
tmp/cache. They were appearing fine a few months ago. Has there been a
recently change?

I don't see cache when running in production mode locally. Cache is
switched on:
config.action_controller.perform_caching = true

I don't see 'fragment cache hit' messages in server log. The section
that is supposed to be cached gets rendered as if no caching is in
place.

I am caching like so(in haml):
- cache :key => "homepage" do
  ...

I am also not seeing it on my remote server with mod_rails.

I have tried everything and nothing works. Can anyone shed some light on
my plight?

Zac Zheng wrote:

This is working now.

It isn't creating cache files when the server is run locally, but does
on the remote server. Hurray!

The fragment cache files are invisible, i.e: they have a dot in front of
them.