For example, when external requests from a web user are directed to different web servers, the user’s state has to be tracked independent of which server is handling the request. This information tends to be rapidly updated and often needs to be shared across all application servers. In-memory data grids (IMDGs) add tremendous value to this scenario by providing a sharable, in-memory repository for an application’s fast-changing state information, such as shopping carts, financial transactions, pending orders, geolocation information, machine state, etc. Flexible pricing options on some public clouds ranging from hourly to annual charges per instance give organizations the ability to cost-effectively outsource hosting for their production applications. And after a period of peak demand subsides, resources can be dialed back to minimize cost without compromising quality of service. Being able to add computing resources on demand keeps work queues small and ensures that web users always see fast response times.
![cost of idmg cost of idmg](https://static.wixstatic.com/media/ba67d9_2dce9a353d2649b2b51b11754df71661~mv2_d_3259_1993_s_2.jpg)
For example, consider a web server farm handling requests for web users or mobile apps. As more computing resources are needed to handle a growing workload, virtual servers (also called cloud “ instances”) can be added to take up the slack. Cloud-based applications enjoy the unique elasticity that cloud infrastructures provide.