Support Redis Clusters with Redis 7 & SSubscribe/SPublish

[tomap]

Hello,

Currently, the way to scale out SignalR servers is to rely on a backplane.
Unfortunately, this backplane cannot be made redundant by using a Redis Cluster because the current behavior of SignalR is to use Subscribe/Publish commands which are not relayed to the other nodes of a redis cluster

Redis 7 introduced SSubscribe & SPublish which is a pub sub mecanism compatible with cluster (aka messages are relayed to every node of the cluster)
https://redis.io/docs/manual/pubsub/#sharded-pubsub
This could be a way to support Redis Clusters

The current status is that StackExchange.Redis does not support those new commands, but work is tracked here:
StackExchange/StackExchange.Redis#2055
Hopefully, once the work is done on StackExchange.Redis side, SignalR can pickup from there to use those new features

For reference: #7814 (comment)

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Document Details

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• ID: c548355c-d88f-b941-0622-56732973123b
• Version Independent ID: bddd7575-422d-4342-af48-f6b0979fb69a
• Content: Redis backplane for ASP.NET Core SignalR scale-out
• Content Source: aspnetcore/signalr/redis-backplane.md
• Product: aspnet-core
• Technology: aspnetcore-signalr
• GitHub Login: @bradygaster
• Microsoft Alias: bradyg

[guardrex]

Hello @tomap ... Is this a documentation-only request, or does the support you're requesting require updates to SignalR in the framework? ... then docs later if the product unit decides to take on the request.

[tomap]

Indeed, I'll post a request on SignalR repository :)

Edit: done. see link below

[guardrex]

Ok, thanks. We try to keep a clean backlog here. If they adopt it in the framework for a future release, it will go on a roadmap tracking issue on their side + get 8.0 labeling. We then draw new issues from there, so we can close this.