DvSwitch configuration retention duration in vCenter failure

[RanjnaAggarwal]

For how long dvswitch configuration is retained at the host level if vcenter is not available for long time period like 1-2 days.

[MKguy]

The dvSwitch configuration does not expire or anything. All hosts will retain the config and VMs will continue to run normally, even if your vCenter continues to be down for ages.

You won't be able to make changes to the existing dvSwitch (add new VMs, change port groups etc) as long as your vCenter is unavailable though.

[RanjnaAggarwal]

but is it was in vsphere 4 because i read it somewhere something about this.

[MKguy]

I'm not aware of any such limitation in vSphere 4 and doubt there really was anything like it. Unless you can dig up the source to your assumption I wouldn't be so sure of a vague memory of having read something somewhere.

[JPM300]

Are you refering to the LBT option on a VDS when vCenter is down.  I can't find the documentation at the moment but I don't think any Load Balancing would happen bettween the nics setup on the LBT in the VDS while vCenter is down as vCenter is what is tracking the load on the nics / re-distributing as needed.  By this I mean if you have LBT enabled on your VDS if it see's to many VM's are using one path/uplink NIC it will move some of the Vm's over to another to reduce the load on that path.

However as posted above the acutal configuration of your VDS is stored on the host and will run just fine with vCenter down for long periods(days,week,ect) You just can't make any changes until vCenter is back online.

If anyone else can find that documenation on what happens with the LBT option in a vDS when vCenter is down feel free to correct me.

[RanjnaAggarwal]

i am not asking about LBT only i am asking if vcenter is down for 1 day suppose then what would happen with shadow switches those were on esxi.

[JPM300]

I'm not sure as to what you are refferring to as "Shadow Switches" however I can assume you mean the VDS switches vCenter created on the hosts, in which case yes you can have vCenter down and everything will still communciate fine.  You just can't make any VDS changes until vCenter is back online.  For Example add another uplink nic to the VDS, create a port group ect.

This is cut from the VDS best practices pdf on page 7:

When provisioned, hosts and virtual machine networks operate independently of vCenter Server.  All components requried for networking switching reside on ESXI hosts.  Even if the vCenter Server system fails, the hosts and virtual machines will still be able to communicate.

http://www.vmware.com/files/pdf/techpaper/vsphere-distributed-switch-best-practices.pdf

I hope this helps

[RanjnaAggarwal]

Please check this, this is what i read it somewhwere

[JPM300]

"vDS is not as convenient as vSS which only connects to single host.  Sometimes, it's not easy to remove vDS switches or even switch physical nic to different vDS switches.  If vDS belives a port is busy, vCenter won't allow you to delete vDS or remove a host from it.  "

What this is trying to say is "sometimes" vDS may prevent you from removing a vDS switch or removing a host from a vDS switch due to active ports being used on this.  I haven't experenced this and would imagine there is a work around to the problem.  One article I found is:

http://pubs.vmware.com/vsphere-55/index.jsp?topic=%2Fcom.vmware.vsphere.troubleshooting.doc%2FGUID-0...

Also where is this referenced from? as this could be an issue that they have resloved since 4.0/4.1 days of vDS.

Also if there isn't a feature set that you require or want to leverage out of VDS you can stick with Standard Virtual Switches if you like.  I see many smaller enviroments for 4-6 node clusters that just stick with Standard Switches as they only get new hardware every 5 years to replace hosts and don't need/want any of the extra feature sets VDS brings.