Storage IO Erros With virtio-scsi Controller When Host I/O Cache is Enabled => fixed in SVN/next 7.0.x and 6.1.x maintenance

[Miky.Ne]

On Ubuntu Server 20.04 guest in Virtualbox 6.1.2 on a Win10 (2004) host: I've selected the virtio-scsi controller and enabled the host I/O cache option to maximize performance. With this configuration, I see multiple I/O related errors in the guest's shell and dmesg log ("Buffer I/O error on device sda2, logical block xxxxxxx", "I/O error, dev sda, sector yyyyyy op 0x0:(READ) flags 0x80700 phys_seg 20 prio class 0", and many others). On the host's log I see multiple messages like "SCSI#0: Read at offset xxxxxxxxx (4096 bytes left) returned rc=VERR_NOT_IMPLEMENTED".

All above errors disappear when host I/O cache is disabled. This seems to have started with Virtualbox 6.1.2. When downgrading to Virtuabox 6.1.0 There are no problems when cache is enabled.

Attached are 2 logs for the same machine (created and running on Virtualbox 6.1.2), one with the cache enabled and the other disabled.

Any help will be much appreciated.

I have reported the problem in the Virtualbox forums:​https://forums.virtualbox.org/viewtopic.php?f=3&t=98962, no responses.

[wsherman]

I have the same issue if using >1 CPU, virtio-scsi, and host I/O cache.

Host OS: MX Linux (Debian based)
Host Kernel: 5.12.0-8.1-liquorix-amd64 (preempt)
VirtualBox version: 6.1.22
Guest OS: Xubuntu 20.04 w/ latest updates installed

1 CPU for VM
AHCI (Host I/O Cache on or off) = OK
virtio-scsi (Host I/O Cache on or off) = OK

2 CPU for VM
AHCI (Host I/O Cache on or off) = OK
virtio-scsi (Host I/O Cache off) = OK
virtio-scsi (Host I/O Cache on) = BAD (I/O errors)

[kdsys]

I have the same issue!!!!!!!!!!!

I have the same issue if using >1 CPU, virtio-scsi, and host I/O cache.

Host OS: Windows 10 10.0.19043.1889

Host Kernel: 5.15.0-46-generic

VirtualBox version: 6.1.36

Guest OS: Xubuntu 20.04.1 latest updates installed

[aeichner]

Will be fixed in the next 7.0.x and6.1.x maintenance releases, thanks for the report!

[galitsyn]

VirtualBox 7.0.4 was just released and available for download at https://www.virtualbox.org/wiki/Downloads. This issue should be fixed in this version.