Bad performance virtio storage driver within libvirt qemu-kvm

Solution In Progress - Updated -


  • The performance of the virtio driver within libvirt qemu-kvm is very low for writes.

  • When we deploy a virtual machine with the virtio driver, we have a write performance of 50MiB/s. When we have a similar virtual machine with the sata driver configured, we have a write performance of 950MiB/s.

  • We want to use the virtio driver, because it has less impact on the system than the sata driver.

  • We use version 4.2.0-19.module+el8.2.0+6296+6b821950.x86_64 of qemu-kvm and 6.0.0-17.module+el8.2.0+6257+0d066c28.x86_64 of libvirt-deamon-kvm

  • We use ceph as storage backend.

  • Is there a fix for the libvirt driver or is this a known issue


  • Red Hat OpenStack Platform 15.0 (RHOSP)

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