Connecting Dual Cable Connected Servers

I prefer to setup servers that can do cable redundancy with LACP, using either Brocade’s MCT or Cisco’s VPC technology. If you are not familiar with these terms, MCT is Multi-Chassis Trunking, while VPC is Virtual Port Channel. These two technologies perform a similar functions. They allow two switches to perform a LAG or Etherchannel to a single device like a server or another switch.

Servers that have dual connections, I try to connect them to the same port on each of the two switches. This makes it easy to figure out what port on the other switch the server is connected to. I feel this is the best way to provide redundancy to servers with cable redundancy. Using LACP with MCT or VPC gives the server double the bandwidth and eliminates the possibility of a spanning tree loop through the server…. Yes, I have had this happen before.

When I have systems that consist of two servers that are single cable connected, I still connect them over the two switches, on the same port numbers. I don’t have to worry about loops because they are two separate servers. Cisco’s CUCCX servers are a good example of this. This system is so important that we have a second server. If one switch fails the application will fail over to the other server and keep the system up and running.

What about those single cable connected server? I prefer to connect them to a single layer 2 switch with redundant power, redundant management module and redundant switch fabrics.

How do you prefer to connect your dual homed servers?
Do you keep the ports assignments the same across both switches?
Let me know, I would like to hear from you!!

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