dbrd live migration, what is actually happening under the hood?

[nate]

I noticed that live migration does take a couple minuets when I migrate a windows server. Depending on the size of the vm.

What I would like to understand is on a live migration with DBRD, what is actually going on under the hood. Since the dbrd volume is synced why does it take so long, what is really getting moved?

Is is it just the vm config or is it snapshot, how does it work?

Thanks!

 

[udo]

I noticed that live migration does take a couple minuets when I migrate a windows server. Depending on the size of the vm.

What I would like to understand is on a live migration with DBRD, what is actually going on under the hood. Since the dbrd volume is synced why does it take so long, what is really getting moved?

Is is it just the vm config or is it snapshot, how does it work?

Thanks!

Hi,
the config is very small - that not the problem.
It's takes time to sync the memory of the vm to the second node (if the vm is very busy it's can take a long time). At the last moment the vm will freezed and the rest of memory and system-state (cpu-register and so on) will transfered and started again on the other side.

Udo