V2V : virt-v2v supports up to 4 disk devices only

Latest response
Hi everyone

Hit an issues when attempting to migrate a VM using virt-v2v.  Running it in TRACE and DEBUG mode showed the problem as :-

"qemu: too many IDE bus"

Seems that is only supports VM's with 4 or less associated storage devices. 

This issue is internally tracked by Bug 681255:

   Bug 681255 - virt-v2v failed with error  
   https://bugzilla.redhat.com/show_bug.cgi?id=681255

   Note: You will not be able to access above bugzilla because it is internal and private.


Apparently, it's also 2 years old.


Responses

Thanks for the tip-off, Rich.  Were you looking for any particular info or confirmation on this issue, or just raising visibility and sharing it with the folks here?

This is entirely based on assumption - but I believe a VM can only have 4 x IDE devices using other Enterprise Hypervisors.  IIRC you would not be presented with the option to create additional IDE controllers either.  I never questioned this as most of my physical machines (that had IDE) generally were limited to only 4 IDE devices and I just assumed that they were replicating the limitations of a physical IDE controller.

Does the VM  you are migrating have more than 4 IDE devices?  Or is the conversion detecting something incorrectly?

I understand you may not be looking for assistance, but if you figure out a workaround would you please update the thread as this sounds like a situation that other people may find themselves in.

Thanks!

I think that libguesfs is actually detecting the devices incorrectly and assuming they are IDE when in fact they are virtio.

The clue is in the debug output from virt-v2v which states "iface:ide" for the disk devices, not "virtio" as I would have expected.

 

libguestfs: trace: add_drive_opts "/tmp/AQs7zQhYSa/fc5430af-a43f-4721-9041-780cb041d74f/v2v.qZyVrq5A/6ad7d1ae-bde7-4803-9ce3-250cf3b86051/44539427-121d-4058-8654-63e42e51f9ee" "format:raw" "iface:ide" "name:vda"

libguestfs: trace: add_drive_opts = 0

libguestfs: trace: add_drive_opts "/tmp/AQs7zQhYSa/fc5430af-a43f-4721-9041-780cb041d74f/v2v.qZyVrq5A/d48eee4e-bf7b-4a17-bef7-19d86393f5e7/c9cf62f2-9496-4ad6-8566-68cd684d3344" "format:raw" "iface:ide" "name:vdb"

libguestfs: trace: add_drive_opts = 0

libguestfs: trace: add_drive_opts "/tmp/AQs7zQhYSa/fc5430af-a43f-4721-9041-780cb041d74f/v2v.qZyVrq5A/d0c85d93-bbb3-4f3a-9863-cf4c24529ca4/726d7765-1955-484a-905b-5c1771664e27" "format:raw" "iface:ide" "name:vdc"

libguestfs: trace: add_drive_opts = 0

libguestfs: trace: add_drive_opts "/tmp/AQs7zQhYSa/fc5430af-a43f-4721-9041-780cb041d74f/v2v.qZyVrq5A/9a6ffe81-7eb8-4892-8697-ca656f891598/8cc2982e-44e3-4a46-b163-fbc59ffcacd0" "format:raw" "iface:ide" "name:vdd"

libguestfs: trace: add_drive_opts = 0

libguestfs: trace: add_drive_opts "/tmp/AQs7zQhYSa/fc5430af-a43f-4721-9041-780cb041d74f/v2v.qZyVrq5A/2e62e462-6ad4-41b4-8314-0ef4a4b753c2/72b30ab0-a2ee-4bde-ad42-89a95e2fa1d0" "format:raw" "iface:ide" "name:vde"

libguestfs: trace: add_drive_opts = 0

libguestfs: trace: add_drive_opts "/tmp/Pc6XssuH0x" "readonly:true" "format:raw" "iface:ide"

..and then later on, this clanger...

qemu: too many IDE bus

 

Because we were pressed for time, I simply consolidated the four disks onto one new, fat disk using pvmove, removed the four disks from LVM control and from the VM xml config before successfully migrating using virt-v2v.  Doesn't fix the underlyinmg issue though , so I will press on with a resolution.

Cheers