Hi,

Does anybody have any guidelines (even if it's just a rough MB/sec) on how long a VHD to VHDX conversion would take?  I have a VHD which is 1.8TB that I need to convert to a VHDX so I can expand it further, but I wanted to get an idea of how long the process is likely to take. 

• Edited by adamf83 Monday, April 28, 2014 6:29 PM

Hi,

Does anybody have any guidelines (even if it's just a rough MB/sec) on how long a VHD to VHDX conversion would take?  I have a VHD which is 1.8TB that I need to convert to a VHDX so I can expand it further, but I wanted to get an idea of how long the process is likely to take. 

If both source VHD and destination VHDX are on the same LUN it's not going to happen fast - reads, writes and seeks are going to be combined. Get Intel I/O Meter and run 1 worker, 16 I/Os in a queue, 50% read / 50% write, 100% sequential, 64KB I/Os. Number you'll have would be X and time = 1.8TB / X. If VHD and VHDX would sit on a different LUNs you'll eliminate seeks and thus time would be slowest from source read and destination write. Hope this helped :)  

 Totally agree with  VR38DETT. Pretty sure that this is the best answer that you`ll get here. 

I guess I can only suggest some V2V converter tool. Here are some:

StarWind solution: http://www.starwindsoftware.com/converter

5 nine solution: http://www.5nine.com/vmware-hyper-v-v2v-conversion-free.aspx

MS solution: http://blogs.technet.com/b/scvmm/archive/2012/09/18/free-tool-to-convert-vmware-based-virtual-machines-and-disks-to-hyper-v-based-virtual-machines-and-disks.aspx

• Edited by AnatolySV Tuesday, April 29, 2014 1:48 PM
• Proposed as answer by VR38DETTMVP 1 hour 50 minutes ago

Thanks... With that in mind, am I right in thinking that the conversion process just creates a VHDX alongside the existing VHD.  If the conversion ends up taking longer than I've worked out or we run into problems, does the existing VHD remain usable so I could just re-attach it if need be?

Hi,

Totally agree with  VR38DETT too, the time cost will effected so much conditions, The converts a virtual hard disk file, the process is copying the data from a source virtual hard disk file to a new virtual hard disk file of a specified format and version type, so it similar the copy file, it most effected by your storage performance, such as RAID type, storage type (iSCSI or FC SAN).

More information:

How to convert between VHD and VHDX formats in System Center 2012 Virtual Machine Manager

http://support.microsoft.com/kb/2799257/en-us

Hope this helps.

Thanks... With that in mind, am I right in thinking that the conversion process just creates a VHDX alongside the existing VHD.  If the conversion ends up taking longer than I've worked out or we run into problems, does the existing VHD remain usable so I could just re-attach it if need be?

Original content is not replaced by any conversion tool I know so think about this process as about creating backup copy (very much simplified). Sure source VHD is usable.