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Best Practices when using MVMC to improve speed of vmdk download RRS feed

  • Question

  • I've converted a number of machines already from ESXi4.1 to Hyper-V 2012 successfully and learnt pretty much all the gotchas and potential issues to avoid along the way, but I'm still stuck with extremely slow downloading of the source vmdk files to the host i'm using for the MVMC. This is not so much an issue for my smaller VM's but it will be once I hit the monster sized ones.

    To give you an idea on a 1GB network it took me 3 hours to download an 80GB VM. Monitoring the network card on the hyper-v host I have MVMC running on shows that i'm at best getting 30-40Mbs download and there are large patches where that falls right down to 20Kbs or thereabouts before ramping back up to the Mbs range again. There are no physical network issues that should be causing this as far as I can see.

    Is there some undocumented trick to get this working at an acceptable speed? 

    Copying large files from a windows guest VM on the esx infrastructure to the Hyper-V host does not have this issue and I get the full consistent bandwidth.

    Thursday, January 10, 2013 5:02 PM

All replies

  • I really want to bump this thread. I get about 40-50Mbit/s when migrating over gigabit LAN.

    I tested two small servers yesterday as test with approx. 150GB of data. Tonight I'm going to do the rest of the 3,5TB...  :(

    Anyone have have some tips?

    Regards, Sebastian

    (MS Certified Hyper-V Geek)

    Friday, February 1, 2013 3:09 PM
  • Are you doing a single conversion or multiple conversions in parallel (running multiple instances of the mvmc wizard for example)?
    Tuesday, February 5, 2013 8:37 PM
  • Did you ever find the solution to this issue?  I'm testing the new MVMC 2.0 tool to migrate from vsphere 5.1 to hyper-v 2012 r2 and am seeing similar network speeds for no good reason.
    Sunday, June 22, 2014 9:51 PM
  • It's VMWARE in general is why... Ever since I can remember (which was ESX 3.5) if you copy using the webservice from the data store the speeds are terrible. Back in the 3.5 days the max speed was 10Mbps as second. FASTSCP came around and threaded it to make it fast.

    Backup software like Veeam goes faster only if you have a backup proxy that has access to all data stores running in VMware. It will then utilize the backend VMware pipe and VM network to move the machines which is much faster.

    That being said in theory if you nested a Hyper-V server in a VMWARE VM just for conversations it would be fast permitting the VM server has access to all the datastores.

    Oh and if you look at MAT and MVMC the reason why its fast is because netapp does some SAN offloading to get around VMWARE and make it array based. So then its crazy fast.

    As a side not that was always one thing that has pissed me off about VMWARE.


    Sunday, August 10, 2014 9:47 PM
  • If you have just a bunch of critical Windows-Based VMs, i suggest the use of the well-known tool "Disk2VHD". Run it directly out of the VM. 

    PROs are:
    - thin provisioned VHDX, copies only used space
    - no need for temporary thick-VMDK storage with the full size
    - up to 5x faster than Microsoft Virtual Machine Converter

    I used this method to convert a DC + Exchange in one night. Due to the allocated size it would not be possible with the Virtual Machine Converter.

    Of course this is nothing for a bunch of VMs, just for the critical ones :-)

    Thursday, February 25, 2016 10:52 PM