Clustering Failover

[McChikenhanger]

Hi guys,

 

Just a quick question. I have set up a test Hyper-V cluster, and all works fine. Apart from if I perform a live migration, towards the end of the migration, once the VM is being switched over from Hosts then there's a slight blip in the connection to the VM.

 

Is this behavior normal? Or should the change over should be completely seamless? I.e. if we are logged in to the VM, we don't get kicked out by the live migration process towards the end.

 

Kind regards you all.

[pantscat]

Depends on your definition of seamless!

 

Essentially, no, it's not completely seamless due to the fact that the IP has to be associated with a new physical mac address, therefore some network connectivity will be lost.

 

If you were to do a "ping -t" on the IP address while the migration is going on, you'll probably see one or two packets get dropped. It's normal in my experience.

[FN-GM]

It would be normal for 1 packet to get dropped. But you wouldn't really notice it as most traffic is TCP and can handle that. If you have something that runs UDP it will loose the packet. For something like a DNS that wouldn't matter, but for a IP Phone system you would notice a crackle or robot like sound in the call.

 

But how often would you do these live migrations. Not very often I should think.

[localzuk]

You shouldn't see any "kicking", the blip is tiny - I've migrated RDS servers during working hours before and no-one has been kicked.

[FN-GM]

You shouldn't see any "kicking", the blip is tiny - I've migrated RDS servers during working hours before and no-one has been kicked.

 

What he said

 

However if you have the console to a server open in Hyper-V manager it will close this. But this is down to the fact the VM has moved and not down to network connectivity.

[McChikenhanger]

Thank you for all of your replies guys. I guess I will try the migrations from the user's perspective. Might put a test SIMS server in the cluster, and I'll have some test PCs as a workstation. Then I'll do a live migration with people connected to the database, and see if they lose connection to the database or not.

 

My main worry is that the SIMS server can't deal with the migrations too well with users logged to the databases, and I don't want them to get locked or anything.

 

Thanks all.

[FN-GM]

My main worry is that the SIMS server can't deal with the migrations too well with users logged to the databases, and I don't want them to get locked or anything.

 

It doesn't on our Hyper-V cluster.

 

Thanks

[McChikenhanger]

Ah sweet. That's good to hear. I guess that answers my question. Full steam ahead then. After a bit more of testing obviously.