Backend Robot installation

I am new about Uipath so forgive me if the questions are trivial.

Question 1:
Where are the backend robots installed? I understood in a server other than the orchestrator, SQL server and Indexer Server. Is this correct?

Question 2:
In such case, what is the sizing of such server? Same sizing of the orchestrator i.e. to host 10-200 robots it is recomended to have a 8 X 2.4Ghz cores, RAM 32GB, HDD(*) 600-800GB server?

Question 3:
Should be forseen a couple of machines (hosting the robots) in order to have High availability as it is done per Orchestrator (via NLB) and DB clusters?

Question 4:
For demo purposes, if only 2 servers are available what is the configuration?
1 server: Orchestrator + SQL Server
1 server: Indexer
1 server: Orchestrator + Indexer
1 server: SQL server

In UiPath Orchestrator Architecture 2016.2 it is recomended to “If the SQL Server is not installed on a separate machine, we recommend to install it along with the Web Application Component . This leaves the Indexer Server alone, on a separate machine, due to resources requirements.” but later in the hardware description it is shown to install “Web Application Server and ElasticSearch” together and the SQL server alone.

Thanks for your support

let me know if I can further help


Hi Gabriel,
thanks for the replies but I still have a couple of doubts.

For question 1: I do understand that tipical set up (without High Availability) would be:
-1 server or Virtual machine hosting the Orchestrator software
-1 server or Virtual machine hosting the SQL server
-1 server or Virtual machine hosting the indexer (optional)
-1 server or Virtual machine hosting the backend robots sized as per reply to question 2. (i.e. if I have 10 robots I will need a server with 20-40 GB of RAM)

For question 3:
if I am not mistaken such documentation explains how to make orchestrator and SQL redundant. What I wonder is if the same happens to the server hosting the backned robots. I.e. I have a server with backend robots and in case this server fails I will have another server where to start again the robots


Is it necessary to have all the servers on different machines or some of the components can be clubbed together, like orchestrator and SQL server, on one machine and other on a different one? Also is it necessary to have a separate indexer, like elastic search, or can just database logging suffice?