at the moment about 250 users with jabber 9.1.5 are online. (9.6.0 is being prepared for rollout the next time)
We are recognizing a high CPU load on the Microsoft Active Directory Conroller which I set as the directory server (sometimes 100% vor a few minutes)
Its connected over the Global Catalog port for 4 Domains where all users are placed.
Which directory did you use for jabber clients?
Have other companys this problem too, espacially with more clients? (we plan about 1000 users concurrent)
Please take a look at this section, are the AD attributes suggested indexed? Are you sure high CPU it is definitely related to Jabber activity?
Attributes on the Directory Server
This may be the reason for high CPU. Do you need to point to the Global Catalog instead? Are the attributes replicated on the GC?