Invalid disk format when downloading to local storage.

[SviridoffA]

problem

When we downloading disk locally, it’s transferred to secondary storage, and we receive a download link. If we are using primary storage that works with RAW disks, such as Linstor, file on the secondary storage will be named, for example, disk.raw. However, this disk is actually in qcow2 format. When attempting to upload this disk back into the cloud infrastructure, we see the .raw extension and try to upload it as a RAW disk. This results in an error:

Volume d7fc1435-ad21-4d32-8951-61b8581c35ef failed to upload. Error details: File type mismatch between the sent file and the actual content. Received: QEMU QCOW2 Image (v3), 1077665792 bytes

If we change file extension to .qcow2 and select this format during upload, disk uploads to the cloud without any errors.

versions

Ubuntu 24.04
ACS 4.19.2
Pr. storage - Linstor
Sec. storage - NFS

The steps to reproduce the bug

1.When you using RAW disks on primary storage, download disk to you local storage.
2. Try uploading this disk back to the cloud, using the settings according to file extension.
3. If you upload this file as a qcow2 disk, it will be successful.

What to do about it?

Incorrect disk format is unclear to user and leads issues when attempting to use this disk after downloading. Downloaded disk file extension needs to be corrected.

[SviridoffA]

Hi @rp- ! I’m sorry to bother you so often :), but could you please take a look at this issue?

[rp-]

AFAIR we(Linstor) have to lie to CloudStack a bit about the format, because CloudStack doesn't store the format of the snapshot.
So we actually tell CloudStack that we have qcow2 volumes, but we are actually not. And this sometimes creates issues like this.
See this comment here:

cloudstack/plugins/storage/volume/linstor/src/main/java/org/apache/cloudstack/storage/datastore/driver/LinstorPrimaryDataStoreDriverImpl.java

Line 1218 in 16c60c7

// patch source format

Once I have time, I can check if we can also patch the format somewhere here, or CloudStack stores the snapshot format.

[SviridoffA]

Thanks for your reply @rp- ! It would be great if plugin could somehow patch the format🙏🏻. Сurrent situation often leads to misunderstandings for users.