When building a datacenter in a network how far would you go to make it redundant? Also is their anything that you should or should do when meshing network - such as are they certain setup's that are likely to casue problems?
The more redundant you are, the more valuable your services are to the end user.
Redundant connectivity:
You need at minimum diverse path from a single provider (The inbound connectivity needs to be fed from a seperate building entrance), and any piece of equipment it touches needs to be redundant, including your own. If both paths touch the same router or switch on the way in at any point, then its not redundant.
Redundant power:
Service:
To be considered fully redundant, you want seperate service feeds from seperate substations that come in through diverse paths. Once again, it can't touch any common gear, or its not N+1. A common ATS or panel, then there is a single point of failure. Same goes for the UPS, if its not split across 2 or fed from seperate PDU's/Panels with seperate breakers and outlets, its not fully redundant.
Cooling:
Most DC's use a chilled water loop and a CRAC unit. If they don't have 2 of them, and their heat load can't be cooled by a single one, then its not redundant.
At the end of the day there are very few buildings or facilities that can claim they don't have a single point of failure. Just because a building has 50 Generators and 100,000 gallons of diesel fuel doesn't mean that this isn't connected to a single piece of gear on the way in.
In my opinion, its more important that the equipment that is used is maintained on a regular schedule and monitored. If you build a beautiful facility and the ignore your equipment, your likely going to have something go wrong down the road that if your save some of your buildout costs and spend that on keeping the equipment up regularly.
Redundancy is the key to building a stable network. Have multiple carriers, multiple routers, and multiple core switches. Make sure though that each of the redundant units can handle the full load of your network by itself or it won't do you much good if it too becomes unaccessable because it was overloaded during an outage.
Really, to have a redundant network it is as simple as that. No netwrok should have ANY single points of failure, imho.
Network Redundancy
