Standby VM Sync Time

Question

It appears that if one export for a standby VM fails then the entire export process begins again. This would be understandable if there was a mandated time or number of data changes for export VM's to remain in "sync" but there isn't. 
 For instance if the queue is backed up RR does not seem to care if the window is missed, it simply does it later. Also, I can set my backup schedule on any given machine for once an hour or once a day and they still stay in "sync" regardless of changes or data moved. 
 Given these things why does RR barf and start over if the hypervisor happens to be off or the network is down for one snapshot? 
 Also in regards to standby VM's. Is it possible for these to "sync" while running or paused? I dare not try it knowing one problem will force me to start over. A process that can take days for large servers.

phuffers · Accepted Answer

The missed job triggering a full export, like I mentioned I'll be happy to check, that is news to me. The failed export though, yup, that will most certainly get you a full export. For the virtual standby itself, that MUST be powered off. Having it powered on, or if you are going in can configuring then you actually are manually creating a situation that we would expect to you to have future issues. As mentioned before that is why the first things we do at the start of the 'next' pass is revert your snapshot that we left open so that it is back to being where we left it when the last job finished. If you are going in and booting them up, editing something customizing we would expect the clone VM to BSOD on you the day you need to use it, as that is essentially 2 hands in the cookie jar editing the VM without the other knowing about it. To answer your question the VM must be off to update it, which is common in the DP industry (or at least to the DP solutions that I have seen/used over the years). 
 Forgive me, I mentioned the scheduling off your mandated time comment, perhaps I misunderstood.

phuffers · Answer

What you are describing is correct, if the export job fails, the core will queue up a full export upon the next pass. The intent here is that the core will not leave your virtual clone's stability up to chance. This is by design as another layer of protection for you so that the day that you go to power on the VM it is there, ready to go, and you have a lesser risk of a configuration issue or BSOD boot cycle. This is an extension of why the first step in each VS pass is that we revert the existing snapshot in VMware or HV so that any booting/changes/modifications that you make to the clone are removed so they are still indeed a clone of the production machine, we're trying our best to make sure that the day you need it, it is there and ready for you.

For your other questions, the virtual standby jobs are set to run after a backup (or a replication on the target core) are complete, if you wanted to automate them, you'd have to pause them from the GUI and then configure a PS script or something of that nature to kick them off at a certain desired time. Or, if it works for you environment you could switch to doing daily backups and then the virtual standby would kick off right after the backup at said desired time.

For the 'queue' you are correct, once the scheduler releases a job into the queue, then the logic is such that that job will run. The scheduler is only set to release the jobs, not to monitor how long they take or govern when they should stop or start. This goes back to the data protection concept, whether the job takes 1 hour or 8 we will continue as one day we expect you will want to restore from that, so we want it intact.

I'll honestly have to test the scenario of the hypervisor being off, as I can't definitively say if this forces a full export or not off-hand. That I'd be happy to test, however I was/am unaware of that result at this point in time, however I'd be happy to test that scenario.

This point, forgive me, I am not sure what you mean?
"Also in regards to standby VM's. Is it possible for these to "sync" while running or paused?"

Are you trying to run an export while the clone VM is powered on? I'm sorry I'm not sure what you mean there.