Network admins hate stretching VLANs across data centers, we absolutely hate it. It causes potential instability on a inter-data center scope, destroys our isolated fault domains; something happens with VLAN X on site A, it also can take down site B (unless you take special precautions). I spent a few hours last week and the week before to help out customers that had that exact issue, which triggered this post.
The entire idea of stretching VLANs between data centers is about virtual machine mobility. You can do a failover between sites and don’t have to make adjustments to your applications … Read more