topic Catalyst Center Cluster Scalability in Software-Defined Access (SD-Access)

Catalyst Center Cluster Scalability

Khusan Egamnazarov — Wed, 20 Aug 2025 12:46:53 GMT

Hello team,

I recently encountered an error message with Catalyst Center cluster consisting of tree DN2-HW-APL-L, the error states "The number of sites exceeded 2100 (105% of limit)" and the other "The number of Wireless Devices exceeded 11050 (85% of limit)".

I also notices some freezes in the system, I found some documents regarding the DNA scalability, however I couldn't find any official document stating the exact limits for cluster setup vs single host. Please let me know if there is any documentation regarding DNA cluster scalability vs DNA on a single host.

Please feel free to comment if additional information is needed.

Re: Catalyst Center Cluster Scalability

Preston Chilcote — Wed, 20 Aug 2025 14:48:08 GMT

For Regular and Large appliances there is no added scale benefit to clustering. Table 14 in this doc has the scale numbers. You can use the DN3 numbers for your DN2 Appliance.

https://www.cisco.com/c/en/us/products/collateral/cloud-systems-management/dna-center/nb-06-dna-center-data-sheet-cte-en.html#Appliancescale

XL Appliances do have some benefit to cluster when it comes to scale (see Table 15 in the same doc).

Re: Catalyst Center Cluster Scalability

Khusan Egamnazarov — Thu, 21 Aug 2025 05:00:54 GMT

Hello Dear Preston,
Thank you for your reply,

Could you please specify which line in the Table 14 and 15 are you referring to for Devices and Sites?
What is the limits of my cluster for Devices and Sites?
What are the options for me to fix those errors?

Thank you for your help!

Re: Catalyst Center Cluster Scalability

Preston Chilcote — Thu, 21 Aug 2025 16:46:33 GMT

The "Site Elements" Row will give you numbers for Sites. You'll find 5000 as the limit for a Large appliance, which doesn't match the 2000 reported in your error message, but that probably means you are running a release prior to the increased scale. If so, a simple software upgrade of Catalyst Center should solve that Site Elements error, but not the wireless devices.

For Devices, note that APs are treated separately from Routers, Switches, and WLCs, so they aren't counted in "Devices". Assuming no Software Defined Access (SDA), a Single Large appliance can handle "2000 (Switch, Router, WLC) + 6000 APs". A single XLarge appliance can do "5000 (Switch, Router, WLC) + 13000 APs". Table 15 explains that a cluster of XL appliances can do 10,000 Devices and 25,000 APs