We currently use Redis to store the session of one application currently running on Azure. We use it so when Azure scales the application the session is not stored locally in the application itself. We are in the process of placing another application in Azure too, and I'd like to know if we can use that same Redis instance, or if having two applications storing sessions on the same place might cause issues.
2 Answers
I wouldn't use different keys and the same Redis server and database. Your two web apps become co-joined twins. If one web app acts up, it can tank the other one.
If you're deploying the same web app code to two or more web apps, you could use the same Redis server but different databases within the server. Azure Redis Cache has one server, each with 16 databases. However, databases within the same server share service limits.
Or the absolute best thing to do is firewall the two web apps by using two different Azure Redis cache services.
It depends on your key. If you use a key that is only the user name. Then both applications read the same session state. You could do it by creating a composite key with the application name as part of the key.
I would use a seperate instances:
- ensuring unique key names across applications adds complexity and risk
- high load on one application can impact other applications
- if the Redis instance goes down alle your applications fail
Related