Our system has 4 live servers on a load balancer in an Amazon Cloud. We are using memcached but don't understand it very well, previous programmers implemented it.
Any user that goes to our site will be using one of the 4 live servers and all are supposed to be in sync and have the same data. We have a bug that when a write is done, the other servers are not updated until after several hours so there is not consistent data between them. All 4 use the same database. We see in our code that memcache is deleted when a write is done but it seems that it is only done for that one server, we want that it should be cleared for that one piece of data on all servers. Any ideas how we can fix this? Thank you for your help.
