Migration VMs between vCenter very slow

[Jesus Quintero]

Hi,

I am trying to migrate VMs from one vCenter to another using Cross vCenter vMotion  but the migration takes a long time to complete.

The VMs are configured with Thin format.
The source storage is VMFS 5 and destination VMFS 6.

Maybe this could be part of the problem that the migration is very, very slow? 

[mviel]

Jesus ,  I have done many Migration "Cross vCenter vMotion" .  It depent what you define as "very, very" slow and particular what speed you can achive . Is that maybe a WAN Line you use ? 

You have to count in that the Cross vCenter vMotion Migration is maybe so slow as there are frequent Updates on the VM you try to Migrate and that we hinder and prolong the Migration Process.  The was no Info on the underlying Network, so keep in mind that Latency is curcial too . 

I didnt had a VMFS5 Storage involved and therefor now knowledge if that could be also a case . 

I used a 10GB Management Line to transfer 70TB of Data and that is taking long too , but as Tests showed we decided to shutdown the VMs and then migrated them , it took a long time. All in All it took Days to migrate 1000 VM , and keep in Mind it seems that there is a limitation for 1 VM so it was always faster to migrate many ad the same Time. 

[pcgeek2009]

One thing to consider is the network design between the vCenters. Are they are different VLAN's? If so, the traffic is going all the way up to the router. That is possible capped at a much smaller network speed. Another thing to consider is jumbo frames, once again depending on the network path. That would not be possible across VLAN's or totally different networks. 

[Dave Leaver]

Have you setup a dedicated vmkernal port group for the NFC traffic?  NFC is used for the actual data copy (vMotion only does the compute part) and if you don't have NFC enabled on any VMkernal ports then by default the traffic goes over the management network.  If you have a dedicated VMkernal port group with NFC and vMotion enabled (which will allow multi-stream NFC, which may not be available if you are on older vsphere versions which it sounds like you might be), then it should improve performance.

[Jesus Quintero]

Good morning,

1. We were migrating the  virtual machines power off.
2. One of the things we saw that having Thin format took longer than having Thick format.
3. If the VM was in VMFS5 or VMFS6, the time was approximately the same.
3. In the end, due to time issues, it was decided to share a storage between both vCenter, migrating the VM to that storage, removing the VM from the inventory of the source vCenter and presenting it to the target vCenter.

Thank you very much for your help. 

PS, I will keep your ideas in mind for future migrations!