Well, if you’ve enough h/w resources, it doesn’t matter whether you deploy on one server or distribute them. If its test/dev environment, you can opt for single box….but if its for Prod, I would opt for Best Practices which also suggests having dedicated DB2 host. I had presentation a while ago on Network Mgmt focused, you can see some specifics @ https://ibm.biz/BdZBhc.
You may also find NOI best practices guides handy @ https://ibm.biz/BdZBhd and if you want to include Disaster Recovery(DR) and/or High Availability(HA) into consideration, then the discussion goes little further. Oh, and I would recommend DB2 11.1 Enterprise Edition (as some products require table level partitioning feature) along with latest fixpack (fps can be found @ https://ibm.biz/Bdiuya ) instead of 10.x and as a NOI customer, DB2 comes free. Good luck.