BROCADE IP PRIMER

Configuring SLBGoing back to our initial example, we configured several “port” statementsunder each real server. Each port statement reflects a protocol that we intendto use on that real server. For rs1, it's just HTTP. For rs2 and rs3, it's both HTTPand SMTP. We'll talk more about the “port http url” and “port smtp keepalive”commands in the health check section.There are many other settings that may be configured for an individual realserver. It's beyond the scope of this book to cover them all, but one more thatyou should be aware of is “max-conn” (short for “maximum connections”). TheServerIron sets a default value for maximum connections (this varies dependingon model and software). This is the maximum number of connections theServerIron will sustain on an individual real server. When the maximum isreached, no new traffic will be passed to that real server. If the default is morethan you know your real server can handle, you may change the value:SLB-ServerIron#conf tSLB-ServerIron(config)#server real rs1SLB-ServerIron(config-rs-rs1)#max-conn 150000Here, we've changed the maximum connections allowed for rs1 to be 150,000(defaults are often 1,000,000 or more).Configuring Virtual ServersThe virtual server is where the VIP (Virtual IP) is configured. Here, you assignthe VIPs address, decide which ports it will be listening on, determine whichpredictor method is to be used, and which real servers will be used in the loadbalancing. Virtual servers are configured in much the same way as real servers.Here's an example:SLB-ServerIron#conf tSLB-ServerIron(config)#server virtual-name www 1.2.3.4SLB-ServerIron(config-vs-www)#port httpSLB-ServerIron(config-vs-www)#predictor round-robinSLB-ServerIron(config-vs-www)#bind http rs1 httpSLB-ServerIron(config-vs-www)#bind http rs2 httpSLB-ServerIron(config)#server virtual-name mail 1.2.3.10SLB-ServerIron(config-vs-www)#port smtpSLB-ServerIron(config-vs-www)#port httpSLB-ServerIron(config-vs-www)#predictor least-connSLB-ServerIron(config-vs-www)#bind smtp rs2 smtpSLB-ServerIron(config-vs-www)#bind smtp rs3 smtpSLB-ServerIron(config-vs-www)#bind http rs3 httpHere, we've configured two virtual servers. The first was named “www.” It tellsthe ServerIron to create a VIP (1.2.3.4). The next line “port http” tells theServerIron to listen on TCP 80 for that VIP. The next line defines which predictorshould be used. In this case, we chose “round-robin.” If nothing is chosenfor the predictor, round-robin is the default.Brocade IP Primer 335