Join Brandon Neill for an in-depth discussion in this video Distributed switch architecture, part of VMware vSphere: Configure and Manage VDS.
- [Vocieover] The vSphere distributed switch was first introduced in vSphere 4.1. It provides better management and scalability for large environments and it introduces new networking features that are not available on a standard switch. One important thing to note on the distributed switch is that it does require Enterprise Plus Licensing. So before planning on using distributed switches in your environment, verify your licensing. The architecture of a distributed switch is significantly different then the architecture of a standard switch.
With a standard switch, it's created and managed by each individual ESXi host. So for two ESXi hosts in your environment, you'll create it on one host, you'll create all of your individual port groups and then for the second host, you have to go through the configuration again. Creating the vSwitch and then creating all of the individual port groups. This isn't bad for a small environment, but as your environment grows, it can become very difficult to manage a large number of individual vSwitches. The distributed switch is instead created within vCenter Server, and then that configuration is pushed out to each ESXi host that is added to the distributed switch.
As you add more hosts, the configuration gets pushed out to them as well, and any configuration changes that are made after the fact in vCenter Server will automatically be propagated to all of the ESXi hosts that are connected to that distributed switch. In addition, when a virtual machine is connected to a port on a distributed switch, that port is linked back to port information that is stored within vCenter Server. This means that as the virtual machine moves around your environment through vMotion, that information, including configuration and statistical data, is going to follow the virtual machine.
This allows for us to have more fine grain per port control of a virtual machine. It does however, create some potential issues. If vCenter Server is not available, a virtual machine can't connect to or power on on a distributed switch. The most likely cause of this scenario is an HA event where the host that vCenter Server is running on crashes and thus vCenter Server itself crashes. This is partially alleviated by maintaining cached port information on the datastore where the virtual machine is stored.
This information is stored in the .dvs datafolder and is used to restore a virtual machine port when recovering from an HA event. This cache will however eventually time out and if you're environment is going to be down for more than a couple of hours, it's a good idea to move vCenter Server and it's supporting virtual machines to a standard switch. The distributed switch shares many features in common with a standard switch, including support for 802.1Q, VLAN tagging. Support for IP version six.
NIC teaming algorithms including port ID, source MAC hash and IP hash. Support for Cisco Discovery Protocol and support for outbound traffic shaping. The distributed switch also includes many new features that are not available on a standard switch. The features that are available depend on the version of the distributed switch that you're running. Beginning with 5.0, features included being managed by vCenter Server, at the datacenter level. Support for Private Virtual LANs.
Support for network vMotion, which means that the network information for the virtual machine will follow the virtual machine as it is vMotioned throughout your environment. Support for inbound traffic shaping in addition to outbound traffic shaping. Support for port mirroring and Network I/O Control with user-defined resource pools. Many new features were added in the 5.1 release of the distributed switch. Several of these features will help with the stability and robustness of a distributed switch.
These include network health check, roll back and recovery, and backup and restore. Additional features were added including enhanced port mirroring. Support for elastic ports, meaning that the size of the distributed switch will grow as the number of virtual machines that are connected to it. So you no longer have to worry about predicting the number of ports that you're going to need in advance. Advance MAC address management options. Support for LACP and support for IPFIX, also know as NetFlow version 10.
A couple of new features were added to the 5.5 distributed switch, including enhanced support for LACP and traffic filtering and marking. In the latest version of the distributed switch, the 6.0 version, there are some additional features as well, including Network I/O Control version 3, which functions significantly different then the previous version of Network I/O Control and support for IGMP and MLD snooping for better multitask support. Let's take a look at creating distributed switch in the lab.
- Overview of the vSphere Distributed Switch architecture
- Creating a vSphere Distributed Switch
- Configuring a distributed switch
- Managing distributed switch traffic
- Managing VDS health and recovery options
- Monitoring VDS traffic