Can a Redundant RDS Licensing Server Contain the Same Device CAL Key?

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Can a Redundant RDS Licensing Server Contain the Same Device CAL Key?

Abdul Raafay 20

I have a use case where I need to deploy three RDS Session Hosts. My plan is to install the RDS Licensing Manager and RDS Session Host roles on two of these servers, and only the RDS Session Host role on the third server. All servers will use the first licensing server, and if the first one fails, they will fall back to the second licensing server.

I have purchased three Device CALs, and I plan to add the same license keys on both RDS licensing servers. My question is: will this setup violate Microsoft’s terms, and is this configuration acceptable?

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Answer 1

Finn Dang 955 Independent Advisor

Dear Abdul.

You should not load the same Device CAL key on two RD Licensing servers. Installing the same CAL pack twice creates two active pools from one purchase and isn’t compliant with Microsoft’s licensing terms.

What’s acceptable instead:

Run two licensing servers for redundancy, but split your Device CALs between them (e.g., 2 on Server A, 1 on Server B) and point all Session Hosts at both servers. Multiple license servers in one deployment are supported; each server just needs its own valid CAL pool.
If you want full capacity during a failover, keep the CALs on the primary and have a recovery plan to migrate the pack to the standby server using the Manage/Migrate RDS CALs workflow (Microsoft Clearinghouse). This is the supported way to move CALs during replacement or outage scenarios.
If your scenario allows it, consider Per User CALs instead of Per Device for simpler HA (the license server tracks usage but doesn’t enforce it - you remain responsible for compliance).

These approaches should keep you within terms while giving you resilience.

Best regards,

Finn.

Abdul Raafay 20 Reputation points

2025-10-30T15:41:18.3466667+00:00

Also, can you clarify something? I have three devices that will be connecting to three RDS Session Hosts. I want all three devices to be able to establish multiple sessions across all three RDS Session Hosts.

In that case, should I install the RDS Licensing role on all three RDS Session Hosts and assign one Device CAL to each RDS Licensing Server? My concern is that this setup might not allow all three devices to create multiple sessions on all three RDS Session Hosts.
Finn Dang 955 Reputation points Independent Advisor

2025-10-30T16:24:54.1266667+00:00
You don’t need a license server on every Session Host, and you definitely don’t assign one CAL per server. RDS Device CALs are per-device for the whole deployment - one CAL lets that device open any number of sessions on any number of RD Session Hosts.

Clean setup: run two RD Licensing servers for resilience, install all three Device CALs on one primary server, and configure all three Session Hosts to Per Device mode and to use the same two license servers (primary first, standby second).

Why not 1 CAL on each server? CALs aren’t tied to a particular host. Splitting tiny pools across multiple licensing servers can cause double-issuance and out of CALs warnings when a device hits a host that asks a different licensing server.

If the primary licensing server ever fails, migrate/reissue the CAL pack to the standby via the Microsoft Clearinghouse workflow. That keeps you compliant and restores capacity without duplicating the key.
Abdul Raafay 20 Reputation points

2025-11-01T09:11:01.2566667+00:00

Thankyou so much Finn! This helped a lot!