On-premises, 250 is the supported maximum on a pool that hosts users. 1000 is the supported max on a pool that only hosts a few users that will run large conferences. Online, 250 is the max.
That's the supported limit, the technical limit is as many as you want and have allowed in the policy (you can put in 999999...) but there may be performance issues, thus the supported limit statement.
Hi,
1. 250 is the maximum supported conference size hosted by a regular Lync Server 2013 Front End pool. (Note: 250 is not a hard limit, but a recommendation based on the scalability tests using the recommended hardware and software specifications. The tests were based on the Lync Server 2013 User Models. Thus, the actual usage may be different from the usage scenarios in the user model. The actual usage determines the actual server performance and conference experience.)
2. 5% of users in a pool may be in a conference at any one time (e.g., a pool of 10,000 users could have about 500 users in conferences at one time).
3. There shouldn't be any users homed on the large-meeting pool.
4. A dedicated large-meeting pool can host only one meeting at the same time. In order to support more than one large meetings at the same time, Microsoft recommends setting up multiple dedicated large-meeting pools.
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