Memcached: Update Notification for Client Caches

Let's take the .NET client of Memcached for example:

As we know, if we want to put some data to the cache server, we call some API like Cache.Add(string key, object data), and the memeched client will serialize the data and then send it to the cache servers. If the data is a complex object (has a large object graph), the serialization process might be very slow. So, I try to use 2-level cache: Distributed Cache and In-Memory Cache.

The application code will always ask the In-Memory Cache for the cached data. If the In-Memory Cache does not have the cached data, it will then ask the cache servers for the cach开发者_开发技巧ed data. The performace can benifit from the usage of In-Memory cache, for In-Memory cache need no serialization operation and is much closer to the application.

However, there's a synchronization problem. If one web server modifies the data, it will update the database, its In-Memory Cache and the Distributed Cache. But other web servers won't be notified about this "update" event, so their In-Memory Cache won't be updated.

So the question is: How can other web servers be notified when one web server updates the data (so that they can update their In-Memory Caches)? Thanks!

BTW: I want to synchronize the cached data in a "Push Sync" fashion, that is, the cached data will be updated only when they're changed. Because in my application, there are lots of reads while only some writes.