Description of problem: q35 cdrom sda and virtio-scsi sda duplicated error, VM C7-q35-01 is down with error. Exit message: XML error: target 'sda' duplicated for disk sources '/rhev/data-center/00000001-0001-0001-0001-00000000032d/e850c96d-8ab5-4282-94f8-c82df92a0eb7/images/dcd27e3d-3431-47bf-b987-3777b3f5d5a4/dffc12c9-1577-466b-8e6d-8e7b8591c7c0' and '/rhev/data-center/mnt/glusterSD/jass:_iso/0576d7ca-f224-482e-a04a-01ae1b22ddb4/images/11111111-1111-1111-1111-111111111111/CentOS-7-x86_64-Minimal-1511.iso'. Version-Release number of selected component (if applicable): How reproducible: Steps to Reproduce: 1.create q35 vm, add cdrom iso ,add virtio-scsi disk 2. 3. Actual results: Expected results: Additional info:
This seems to be engine issue caused by sending duplicate index=0 for both virtio-scsi drives and sata cdrom (where scsi & sata share the same scsi protocol, leading to /dev/sd* naming scheme).
Proposing solution: we could duplicate i440fx behavior and have cdrom numbered from slot 2. That would leave first 2 disks (sda, sdb) in a place where sane users would expect, then create a hole (sdc, sdb) for cdrom and continue with disks. The labeling itself depends on libvirt though, that's why having first 2 disks guaranteed sounds the safest. Example: /dev/sda - disk 0, bootable /dev/sdb - disk 1, - /dev/sdc - cdrom 0 /dev/sdb - cdrom 1, sysprep /dev/sd{e,...} - disk {2,n} Without caring whether the actual disks (inside VM) are labeled with or without the hole present.
Any reason not to switch the CDROM to use SCSI and dump SATA (and IDE) ?
I would prefer someone with slightly more Windows knowledge, but this is what I found so far: For Windows to support SCSI cdrom, it needs to have the AHCI "driver" installed. The way it's installed does afaik differ between versions: for Win < 10 it was automatically enabled if the system was installed from SCSI cdrom. It seems that Win 10 requires that to be done manually. On the other hand, SATA doesn't need any special handling on Windows yet still remains valid linux-SCSI-subsystem-capable device.
*** Bug 1480255 has been marked as a duplicate of this bug. ***
Verify with: 4.2.0-0.0.master.20170813134654.gitaee967b.el7.centos Steps: 1. create VM with custom emulated machine q35 2. add cdrom iso 3. add virtio-scsi disk 4. Start VM
This bugzilla is included in oVirt 4.2.0 release, published on Dec 20th 2017. Since the problem described in this bug report should be resolved in oVirt 4.2.0 release, published on Dec 20th 2017, it has been closed with a resolution of CURRENT RELEASE. If the solution does not work for you, please open a new bug report.