How to resolve the failure of creating VMs from older versions of mirrors on cloud platforms

Some users run on older operating systems for historical reasons. When they go to the cloud for industry business, they get errors when creating cloud hosts with these mirrors due to old version system driver problems, or they can't run. What can we do to solve this situation?

Cloud Platform Environment: ZStack Enterprise 3.8.5

Manage Node Environment: Dual Manage Nodes are highly available

Primary Storage Environment: Local Storage

Mirror Server Environment: Mirror Warehouse

Network Environment: Flat Network

Bottom Physical Machine System: ZStack Custom Centos7. 4

The older version of system mirroring does not support Virtio drivers, or the older version of system mirroring Virtio drivers do not support SCSI features, causing installation errors.

1. Older versions of mirrors do not support Virtio-driven installation error solutions

1.   Because the mirroring system is too old, many virtualization drivers do not support creating cloud hosts using mirroring on the platform with the following installation errors, An  Unknown error has occurred.

(Fig.1 Installation error)

2. Find an older version of the mirror in the Cloud Resource Pool-Mirror, and then modify the Mirror Platform Type to Other so that the cloud hosts created with this mirror can be created successfully.

(Figure 2 Replacement Mirror Platform)

2. Older versions of mirrored Virtio drivers do not support SCSI solutions

1. Use RedHat6. Version 5 mirroring creates a cloud host installation on a cloud platform with the following error: No root device "block:/dev/vda2" found

(No disk error found in Figure 3)

(Fig. 4 Installation error)

2.   This is because older versions of Virtio drivers do not support SCSI, so you need to manually change the root cloud disk mode to non-Virtio SCSI mode and turn off Virtio SCSI and the cloud host will enter the system normally after restarting.

(Figure 5 Cloud host root cloud disk)

(Figure 6 turns off the VirtioSCSI feature of the root cloud disk)