Memcache as a service @ AWS

It looks interesting, but not really sure how practical it is from a financial and performance standpoint.

If you look at their pricing, they get you sucked in with that small instance for $0.095/hour. That gives you 1.3gb, 1 ECU and moderate I/O. The size should be fine for most Drupal sites, but the I/O is an area of concern given the number of cache_gets that can happen on a page request. The next bump-up is the $0.38/hour package, which gives you 4 ECUs and high I/O, plus 7.1gb. That would probably fit the majority of Drupal sites out there that need memcache.

So if you go with the large instance and only use it for 1/2 a month, you are paying over $200 for the service. That's the price of a dedicated server, where you can run memcache on your own. Also you got to consider the size of cache objects, which will add to your current host's bandwidth and could lead to more charges for you.

There is also the latency issue. Your lowest latency is going to come from a local network. When dealing with caching like this, keeping latency low should always be a high priority. The higher the latency, the greater risk of running into cache stampedes or pages waiting for lock releases.

I can see it being of benefit for maybe the medium-low sized Drupal sites that can run on a VPS, but anything much larger, you would be better to either run memcache locally or go with APC.