Recent advancements in the OpenStack framework, particularly the integration of optimized QEMU 9 enhanced I/O threading, have significantly elevated virtual machine (VM) block I/O performance when connected to Lightbits software-defined storage nodes.
Leveraging the new I/OThread Virtqueue Mapping feature from QEMU 9.0, we observed substantial gains in storage performance and scalability. Specifically, by assigning multiple dedicated I/O threads to virtio, disk performance becomes markedly efficient and scalable, and of course, can be applied to more mount points and additional VMs.
Our tests focused on a 4 vCPU Rocky Linux VM, running on top of OpenStack Kolla via the Lightbits Cinder plugin, and demonstrated notable performance improvements. Optimized Virtio-blk: leveraging recent QEMU improvements, virtio-blk disks now scale efficiently and maximise the throughput.
Setup pre-requisites
- Kolla OpenStack is configured to run Rocky 9.5 inside the container.
- Lightbits Cinder plugin is configured
- Alma host – 9.4.
- qemu, libvirt, and kernel versions:
- Nova node spec: Dual socket Intel(R) Xeon(R) CPU E5-2603 v4, 12 Cores in total, 64G RAM.
Creation steps
1. Rocky VM creation
2. RSA key creation
3. Create a Rocky VM with the created key
4. Floating IP creation and attachment to the VM
5. Lightbits volume creation and attachment to the VM
6. Apply the following changes to the VM xml schema using libvirt tools:
7. fio runs inside the VM
4K rand read:
Average IOPS achieved: 257K
4K rand write:
Average IOPS achieved: 143K
Note: At these numbers, the bottleneck is still VirtIO and the number of vCPUs/jobs used. Lightbits can deliver much higher performance, and that performance scales as you run more VMs.
For further technical insights, refer to:
- Scaling virtio-blk disk I/O with IOThread Virtqueue Mapping – Red Hat Developer
- QEMU AioContext Removal – vmsplice.net
This utilization of QEMU’s latest features exemplifies how infrastructure improvements within OpenStack can directly amplify performance when coupled with Lightbits’ advanced software-defined storage solutions.
For enterprises looking to maximize the efficiency and scalability of their virtual infrastructure, adopting recent OpenStack enhancements in combination with Lightbits block storage presents a compelling opportunity.
Contact us to explore how these advancements can elevate your data center operations.
