Please take a look at our online documentation for system requirements - http://docs.splunk.com/Documentation/UBA/2.1.0/Install/Requirements . There is a Splunk UBA app that is installed on the Splunk Platform, however it does add its own server or servers to the overall Splunk architecture depending on the deployment size.
Hardware requirements
You can install Splunk UBA on a physical server, a virtual machine, or in the cloud. You must have sudo access to the server. Wherever you install Splunk UBA, the machine must meet the following requirements.
50 GB disk space for the Splunk UBA installation.
500 GB partition or additional disk space for metadata storage.
16 CPU cores.
64 GB RAM.
Operating system requirements
Splunk UBA can only be installed on a server that uses one of the following 64-bit Linux distributions:
Ubuntu 14.04.3 LTS
RedHat Server 6.6
CentOS Server 6.6
The Open Virtual Appliance (OVA) format provided for virtual installations includes 64-bit Ubuntu 14.04.3 LTS.
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