Restore from NAS backup is failing for VM with template / disks < 1 GB

problem

Restore from NAS backup is failing for VM with template / disks < 1 GB, fails with "Root disk size should be a positive number." error.

It seems regression from create VM from backup feature (#10140)

The size computation below, returns 0 for disks < 1 GB.

cloudstack/server/src/main/java/org/apache/cloudstack/backup/BackupManagerImpl.java

Lines 1168 to 1169 in e78b5cc

    
           Long size = volume.getSize() / (1024 * 1024 * 1024); 
        
           rootDiskOffering = new VmDiskInfo(diskOffering, size, volume.getMinIops(), volume.getMaxIops());

cloudstack/server/src/main/java/org/apache/cloudstack/backup/BackupManagerImpl.java

Lines 1192 to 1193 in e78b5cc

    
           Long size = volume.getSize() / (1024 * 1024 * 1024); 
        
           vmDiskInfoList.add(new VmDiskInfo(diskOffering, size, volume.getMinIops(), volume.getMaxIops(), volume.getDeviceId()));

versions

ACS 4.21.0, KVM Hypervisor, NAS repo configured

The steps to reproduce the bug

Register a template (< 1 GB) - http://dl.openvm.eu/cloudstack/macchinina/x86_64/macchinina-kvm.qcow2.bz2
Deploy a VM using the above template
Assign backup offering and take backup
Go to the backup ,and restore from it.

What to do about it?

Support Restore from NAS backup for VM with template / disks < 1 GB, document it if unsupported.

@sureshanaparti

@sureshanaparti I have tried to reproduce the issue with the same steps. I could restore a VM from the backup and also could create a new VM. May this is fixed already. Could you please check and reopen the issue if there is something else needs fixing.

I've tested both on 4.22 and main branch environments.

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Restore from NAS backup is failing for VM with template / disks < 1 GB #11707

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	Long size = volume.getSize() / (1024 * 1024 * 1024);
	rootDiskOffering = new VmDiskInfo(diskOffering, size, volume.getMinIops(), volume.getMaxIops());

	Long size = volume.getSize() / (1024 * 1024 * 1024);
	vmDiskInfoList.add(new VmDiskInfo(diskOffering, size, volume.getMinIops(), volume.getMaxIops(), volume.getDeviceId()));

Restore from NAS backup is failing for VM with template / disks < 1 GB #11707

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harikrishna-patnala commented on Mar 9, 2026

harikrishna-patnala commented on Mar 9, 2026

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