CBR start operation is blocked

Milenko

Hi guys.
I am currently testing Continuous Replication as our way, to migrate our vms from one pool, to another. So i set up a test vm and a replication job on the same pool (different sr), since i dont have the new pool yet. Everything worked fine, job is running and creating the replicated vm. But when i want to start the vm, i will get the warning "Forbidden operation Start operation for this vm is blocked." I could klick "force start" but i am afraid, the universe will dissolve. So what is the best practice for my task? Do i have to recreate the vms and attach the cr disks, or is there a way to unblock the cr vm and use it as the new vm? I will have to migrate about 30 vms with 15TB so i obviously dont want to clone the cr vm to a new one. Or do i?

Kind regards

Milenko

poddingue

I think that blocked start is actually on purpose rather than something gone wrong: XO guards a continuous-replication target, so you can't accidentally boot the replica and have it drift from the source while the job keeps running.
The documented way to bring one up is the failover process (https://docs.xen-orchestra.com/xo5/incremental_replication#failover-process), and for a real cutover, that's just starting the replica on the destination side; there's also a tip there about making a copy first if you want to start it without breaking the CR job on the source.
So, for your pool-to-pool move, I don't think you'd need to recreate the VMs and reattach disks; the failover flow is meant for pretty much exactly this.

I'd test the whole cycle on your one VM before committing the other 30.

Pilow

@Milenko if this is a definitive migration pathway for you, you can force start the replica VM, no problem, you can even delete the replica snapshot.
Just disable the job at source, it will create a new replica VM otherwise

if it is just a test boot of the replica, fast clone it, and start the fast clone (beware of double ip addressing while doing so... source VM should be halted, or replica clone should be started without network)

Milenko

Hello. Thank you for your input. I am aware, that this is more of a warning message, than a error. I´m just trying to figure out, what is my best way to go here.
My plan was:

Setup a repljob for the vm in a lets say hourly interval
On the day of the migration, shutdown the vm and start the last replication manually
Disable the cr job
Start the replicated vm on the new pool, check it and if all is ok, use it as new vm, otherwise start the old vm.

The documentation says "If you want to start a VM on your destination host without breaking the CR jobs". Tbh i dont care about breaking the job. If everything works fine, i dont need it anymore, if not, i can setup a new job pretty fast. I was just wondering, if the new vm will stay in "blocked mode" for ever.

Kind regards