iTechGuides is reader-supported. When you buy through links on our site, we may earn an affiliate commission. As an Amazon Associate I earn from qualifying purchases. Learn more
The available sources do not establish what “QEMU v0.96” refers to or whether that exact source tree included virtio-blk, so its presence in that version cannot be confirmed. They do establish that Anthony Liguori submitted a virtio block device patch to QEMU’s development list on 4 December 2007, and that QEMU later documented virtio-blk as a virtual block device for guests.
What virtio-blk is
Virtio-blk is a virtual block device that QEMU presents to a virtual machine. QEMU’s 2021 configuration article describes it as a choice with a thin software stack and recommends it when performance is a priority. That is configuration guidance, not a benchmark result: performance depends on the host, guest, backing storage and workload.
What the historical record says
The 2007 patch
On 4 December 2007, Anthony Liguori posted a patch titled “virtio block device” to the QEMU development list. The patch description says, “This patch implements the backend support for the virtio block device.” It also describes a design intended to support in-order queueing of a “virtually unlimited size.” Those statements explain the author’s implementation goals; they are not independent measurements of throughput or queue depth.
Quick wins for a faster PC:
Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →Repair Windows errors before they cause bigger problemsFix Now →Scan for outdated or missing drivers - takes under a minuteDriver Scan →The patch description also says the interface passed through guest SCSI commands. That historical design detail should not be confused with a recommendation to use virtio-blk for SCSI passthrough today.
Later compatibility work
A QEMU source-history listing records a change dated 16 July 2009 titled “qdev/compat: virtio-blk-pci 0.10 compatibility.” This documents later compatibility work. It does not identify the contents of a release called QEMU v0.96 and cannot establish whether that version included the device.
The OASIS Virtio 1.4 specification’s revision notes say it documents virtio-blk capacity changes implemented in Linux and QEMU since 2011. That note establishes the stated scope of the specification revision, not additional details about a v0.96 release.
Did QEMU v0.96 support virtio-blk?
That exact version-history question remains unresolved by the available evidence. The sources establish a patch submission in 2007 and later QEMU compatibility work, but do not identify an authoritative release tag or source archive corresponding to “v0.96.” Without that exact release artifact or its release notes, it would be inaccurate to say the device was present, absent or introduced in v0.96.
Recommended Free Tools
Choosing between virtio-blk and virtio-scsi
QEMU’s 2021 configuration guidance distinguishes the devices by use case. Because that article is dated, treat its recommendation as QEMU’s published guidance at that time and check the documentation for the QEMU release you actually run. It does not provide workload-specific benchmark results.
Quick Recap
| Consideration | Virtio-blk | Virtio-scsi |
|---|---|---|
| Disk count | QEMU’s 2021 article favors virtio-scsi when attaching more than 28 disks. It does not state a maximum virtio-blk disk count in the cited guidance. | QEMU’s 2021 article recommends virtio-scsi when attaching more than 28 disks. |
| Full SCSI support | QEMU’s 2021 article recommends virtio-scsi when full SCSI support is required. | QEMU’s 2021 article recommends virtio-scsi when full SCSI support is required. |
| Performance guidance | QEMU’s 2021 article describes virtio-blk as a good choice when performance is a priority; this is not a guarantee for every setup. | No comparative benchmark result is stated in the cited QEMU article. |
| SCSI passthrough | QEMU’s deprecation documentation describes virtio-blk SCSI passthrough as a legacy feature and directs readers who need SCSI passthrough to virtio-scsi. Check the documentation for your specific QEMU release. | QEMU’s deprecation documentation directs readers needing SCSI passthrough to virtio-scsi. |
| Guest drivers and release support | Check guest driver availability and feature support in the documentation for the QEMU version in use. | Check guest driver availability and feature support in the documentation for the QEMU version in use. |
Practical decision checks
- Choose based on how many disks the VM needs and whether it requires full SCSI support or SCSI passthrough.
- Confirm the guest has suitable drivers for the selected device.
- Verify feature support and deprecation status in documentation for the exact QEMU release you plan to use; general guidance from a 2021 article may not cover every later version.
- Do not treat the 2007 patch’s queueing language as a performance result for your workload.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
