You can quickly use clustered sessions in your existing ASP.NET applications without any code change and can immediately see a performance boost in your application. NCache provides high performance in-memory ASP.NET session clustering for web farms that is faster and more scalable than storing them in a database. It is faster because sessions are kept in memory and closer to the ASP.NET application. And, it is more scalable because sessions can be distributed to multiple servers in the farm that can better handle larger load than a database server.
With NCache, you can eliminate the need to use sticky sessions in your load balancer. This significantly improves your application scalability. NCache provides powerful dynamic clustering of sessions. You can replicate or distribute/partition sessions either locally on multiple web servers or on multiple dedicated session caching servers. NCache offers a rich set of features to grow you session clustering from small to large web farms.
ASP.NET Session-State allows for storing session data into custom data source by implementing SessionStateStoreProviderBase class. A session-state store provider has been implemented using NCache to store data into distributed cache.
NCache based Session-State store provider has the following benefits:
No Code Change: NCache Session State Provider can be used in an application without any code change.
Better Performance: Session data being stored in in-memory cache yields maximum performance.
Reliability: By default session is stored in memory of ASP.NET process. If process recycles or application server goes down, session data is lost. With NCache, session data is stored, outside of ASP.NET process, in cache cluster. Any cache topology can be opted to meet the needs of reliability. So in case the application server goes down, session data remains available when ASP.NET process recycles back or application server comes back.
No Need of Sticky Sessions: Using NCache Session State Provider will eliminate the use sticky sessions in load balancer.
NCache Cache Storage-Scalability: NCache Session State Provider uses NCache cache as storage. Here cluster cache can be used to gain better scalability. Working with it allows adding more servers to session cluster at runtime; it results in more scalability and reliability for the application. ASP.NET session clustering for web farms is faster and more scalable than storing them in a database.
Availability, Load Balancing, Fault Tolerance: In a web farm environment, it provides better fault tolerance by keeping session data available at all server nodes in cluster cache to better handle a larger load. This is because sessions can be distributed to multiple servers in the farm. Thus it is safe to say that it results in a high performance. It is suitable for session clustering from small to large web farms.
Cluster Topologies: For session cache, different clustering topologies can be used. Replicated topology offers load balancing of client so that the web application does not suffer during intensive traffic. If partitioned-replica cache is used, it gives high scalability, high reliability to the application and is extremely fast. Sessions can be replicated or distribute/partitioned either locally on multiple web servers or on multiple dedicated session caching servers. For cache topology details, see section Cache Topologies.
Serialized Data: Session data needs to be in serializable form.
Session Lookup in Cache Made Easy: All session data in cache can be retrieved in a single call. NCache provides tag with session. In one single operation all session data with tag can be easily fetched.
Exclusive Locking: To avoid deadlock and data integrity issue, exclusive locks are provided in NCache Session State Provider. Locking is configurable and in default is off.
Locking Release Retry: If exclusive lock is used, locking retries are also configured. In case of concurrent requests, lock release is tried a configured number of times.
Location Affinity: NCache’s Session State Provider 's Location Affinity manages ASP.NET session state across multiple web farms which are geographically separated. For Location Affinity, one 'primary' and one or more 'secondary' caches have to be specified for each web farm. The primary cache will be used for all local traffic, in local region and secondary cache(s) are of distant geographical regions. These are configured in the application's Web.config. This optimization is possible only in .NET 2.0 and later versions.
In This Section
ASP.NET Session State Provider for NCache
Explains how sessions can be stored using NCache's Session State Provider for ASP.NET.
Multi-Region ASP.NET Session State Provider for NCache
Explains how the location affinity feature in NCache can be configured for web farms using clustered caches distributed across multiple regions.