Cisco Nexus distributed switch

[Arkady]

Hello,

We are planning to implement Nexus switch and considering 2 options: 1. leave console and vmotion on a native switch (not distributed one) and move only virtual machines network to Nexus 2. Move everything to Nexus.

Would like to know from users who deployed Nexus their opinions about these options based on their experience with this switch.

Thank you in advance!

[logiboy123]

The only thing that should concern you with regards to the vDS is where your vCenter server is running from. There are no support or maintenance issues with running your service console and/or VMotion on your vDS.

If vCenter is a VM on the inside of your vSphere environment then putting it on a vDS using 4.1 will create circular dependency. Essentially what this means is that you could very easily lose your environment if either networking or vCenter goes down. see;

http://en.wikipedia.org/wiki/Circular_dependency

http://www.virtuallifestyle.nl/2009/12/virtualizing-vcenter-with-vds-another-catch-22/

Apparently the next major point release of vSphere will include much better support and will avoid the circular dependency currently in place.

If you do run vCenter as a VM, then I would create a VM Network port group on vSwitch0 for use exclusively with the vCenter server and then put all other VM Networking across to the vDS.

[Josh26]

The thing about running your management interface on a distributed switch is that it's very easy to accidentally make a change - and find yourself locked out of all your hosts.

Whilst you can make a similar "far reaching" change for a dedicated production Nexus, you can always just "change it back" to revert a mistake. In a vDS as management interface situation, not only are you unable to correct it (since changes propagate from the vcenter installation your host won't be able to contact) but you have no CLI options from the console, meaning a "reset networking" is about your only option.

[logiboy123]

It sounds like you have had an experience. So I stand corrected, it would seem a bad idea at this point to point your management communications on a vDS.

[rick-vanover]

That too is the way I've taken vDS... Keep host management traffic and vCenter on a traditional virtual switch on a VLAN trunked port. Same goes for the out of band management for the host, iLO/DRAC/etc. Though, I usually would do those as an access port (non trunked).

Guest VMs, as s separate virtual switch; load up on vDS!