If the servers are immutable (eg in auto-scale groups) then it's more like beef cattle because you don't expect your servers / cattle to survive to old age. If

If the servers are immutable (eg in auto-scale groups) then it's more like beef cattle because you don't expect your servers / cattle to survive to old age. If they are any servers that cannot be auto created / destroyed without human oversight - or if their downtime breaks other resources along the chain (eg non-clustered DB server) then I'd argue those servers are a little more like dairy cattle.