Veeam Quick Migration and data compression

[codot]

Hello people,

Just a quick and simple question, but I couldn't find a definite answer in the documentation : can you perform a quick migration of a virtual machine between two distinct virtual datacenter managed by two different vCenter with distinct SAN storage ? If you can, will the backup proxy compress and deduplicate the data when transfering the snapshot between the source VM and the target VM ?

Thank you.

Clement.

[foggy]

Yes, you can migrate between different vCenter servers (make sure you have proxies deployed on both sides). The traffic between source and target proxy servers is compressed.

[codot]

Wonderful. I had big doubt about the interest of this new Veeam technology at first, but that's definitively an interesting usecase.

Thank you.

[bhwong]

btw, can it migrate VMs with snapshots? Will the snapshots be migrated as well or will it get merged like Storage vMotion?

[foggy]

Snapshots get consolidated into a single flat file during migration job. If you need to migrate VM along with its snapshots, you can use the File Copy job to copy the entire VM folder to the target location and register it in vSphere. Thanks.

[bhwong]

I see. But VM Copy will increase storage usage and might not be possible if storage is insufficient due to:

1. Having a duplicated copy instead of migration will double the storage usage

2. A VM Copy will convert a thin to thick, potentially expand the storage usage even more.

I suspect that because of the above, the process to copy will also required more time to complete as compared with migration?

[foggy]

1. Having a duplicated copy instead of migration will double the storage usage

Actually, the migration also requires double space on datastore as the source (_migrated) VM is deleted only when the process is complete (as soon as heartbeat is detected from the target VM).

2. A VM Copy will convert a thin to thick, potentially expand the storage usage even more.

Yes, that's true.

I suspect that because of the above, the process to copy will also required more time to complete as compared with migration?

Never tested but it might be so. Aside from thin/thick, also keep in mind that during migration of the running VM we need to sync the changes and that would take some additional time also (while not required for migration of the turned off VM).

[aeccles]

Yes, you can migrate between different vCenter servers (make sure you have proxies deployed on both sides). The traffic between source and target proxy servers is compressed.

Foggy, can you expand on the "make sure you have proxies deployed on both sides" portion of what you said above?

I'm intending to use Quick Migration in the same way - to move my VMs between two different vCenter servers with distinct SAN storage. In my case, the new and old vCenter and Host server share the same switching network and subnet. The new and old SANs will share their same switching and subnet as well.

In this case will I need more than one proxy?

Thank you!

[foggy]

In case of onsite migration, one proxy is enough. Make sure it has access to both source and target hosts/datastores.

[aeccles]

great. One last question - are you aware of any issues I might run into when using quick migration to migrate from ESX4 to ESXi 5.1 ?
It is my understanding that Quick Migration leaves the original VM unchanged (other than "_migrated" appended to the name) so I know I have a way back in case of errors/problems, but if you are aware of any potential issues it's always good to know what's coming

[foggy]

The only caveat I can think of is that the VM will be stopped in case you move it between hosts with non-compatible CPUs. If CPUs are compatible, Veeam B&R uses its SmartSwitch technology to ensure minimum downtime and eliminate data loss during migration.

To be on a completely safe side, I recommend to clear the Delete source VM files upon successful migration check box in the Quick Migration wizard.

[aeccles]

great advice, thanks again.

[bhwong]

How does quick migration compare with vMotion? In vMotion, if the CPU is incompatible, it won't allow migration at all. Quick migration will still proceed? What is the risk if the CPU is indeed incompatible? Will the VM get freezed etc?

[foggy]

Whenever possible, Quick Migration utilizes vMotion or svMotion to relocate VMs. In all other cases, Veeam B&R proprietary technology is used. If you move a VM between two hosts with non-compatible CPUs, the cold switch method is used: the VM is stopped, then changes occurred after the snapshot are transferred, and then the VM is started on the new host.