Running multiple Server daemons on one Linux server
 

Hello everyone,

I'm just curious on what would be the best practice for running multiple server daemons on one server? Or what would be okay with multiple daemons and what would need its own server. Correct me if I"m wrong, but would DNS need its own I'm assuming and maybe a DHCP as well? Just trying to learn to see how other techs have these setup.

Israel

This depends entirely on your requirements.
* Running multiple services on one server keeps hardware cost down. On the other hand, if you someway lose the server - permanently or temporarily - then all services are lost during downtime.
It is also more difficult to keep the server secured with lots of services running.
A small mistake can render all services unreachable,

* Running one service per server is more expensive, you need more/better hardware - even if your servers are virtualized.
One main service per server is the most secure way, for example it is required for PCI-DSS certification.
If you need to replace a server or service, it is a lot easier to configure a new server with only one service.

So it depends on you & your environment.

A few things to keep in mind:

1. Separate services that need to be publicly available from those that don't.
   Some services are more sensible than other, these you want to keep on a separate server and separate subnet. For example, if you run a webserver you might want to keep the database server on a separate server and subnet than the webserver. Then configure firewall to limit access to database.
2. Don't put several heavy services on the same server.
   A database needs really fast disks and better CPU than a webserver (assuming, of course, there's a lot of traffic to your services). So if you're unlucky, when database is working under heavy load other services on that server might become unreachable.
3. DNS, DHCP & NTP are "light" services that are commonly put on same server - the most common in small organisations is to use the firewall for these.