We run Magento EE 1.13 with memcached as our "fast" cache and redis for the "slow" cache. We have a certain memcached key that is getting approximately 70 get requests per second, but 0% hits. This only happens on our production site, which has multiple front end servers and a separate database server.
It seems this particular key is never set, but we can't find where the key is originating from. The key uses a md5 hash "AA_B1B5D70089938E5C32F61E616FD3908D", so that doesn't help to narrow it down.
Where can I look to track down where this key is coming from?