Purpose of Redis
Redis is an in-memory data structure store and is used as a database, cache, and message broker. Redis functions as an in-memory cache for Cherwell server farms.
By connecting every web server to the same Redis, the applications can share state and collaborate. When a server performs an operation, it saves the state of the current user or application to Redis. In a scenario where a user is bounced from one server to the another, each server can pick up from where the previous server left off by retrieving the latest state from Redis.
For a
Cherwell Application
Server,
the cost of synchronizing with Redis is minimal because the Application Server
exchanges a limited amount of information with Redis. For a
Cherwell
web server, Internet Information Services (IIS) holds state for each user in
form of session, and it can reach the size of a few MB (3-5 MB is the typical
size). For every web request going from the
Cherwell
web application to the server, there is an exchange of session state twice with
Redis:
- When the request starts, to retrieve session from Redis.
- When the request ends, to save session to Redis.
For more information and support, refer to Redis.Io.