Description of problem: When creating a guest with 16384 virtio-scsi disks, libvirt fails with: Unable to encode message payload Version-Release number of selected component (if applicable): libvirt-daemon-3.2.0-1.fc27.x86_64 How reproducible: 100% Steps to Reproduce: 1. Create a guest with 16384 virtio-scsi disks. See the attached file for libvirt XML and so on.
Created attachment 1272310 [details] log from libvirt client
Created attachment 1272312 [details] log from libvirtd
As this bz is about payload size restriction in general, it applies to any retrieval! This for instance prohibits defining a static vm configuration with such large config e.g. for block devices (i.e . "virsh dumpxml $domain > $domain.xml;virsh config $domain.xml"), hence requiring to reattach them after the vm got destroyed which can take hours and thus delay related tests. Please mind that the maximum command line length of typically 2 MiB characters is also a limiting factor preventing qemu to start with scaled up VM configurations. Changed prority+severity to get this fixed.
Also, an unrelated virt-clone fails with the same error: # virt-clone -o fedora-36 -n fedora-36-hm --preserve-data -f /dev/rhel/fedora-36-hm ERROR Unable to encode message payload
Thank you for reporting this issue to the libvirt project. Unfortunately we have been unable to resolve this issue due to insufficient maintainer capacity and it will now be closed. This is not a reflection on the possible validity of the issue, merely the lack of resources to investigate and address it, for which we apologise. If you none the less feel the issue is still important, you may choose to report it again at the new project issue tracker https://gitlab.com/libvirt/libvirt/-/issues The project also welcomes contribution from anyone who believes they can provide a solution.