Opened 4 years ago
Last modified 3 years ago
#20000 new defect
Linux guests lock up with Host I/O cache disabled (NVMe and SATA)
| Reported by: | Hamish McIntyre-Bhatty | Owned by: | |
|---|---|---|---|
| Component: | virtual disk | Version: | VirtualBox 6.1.14 |
| Keywords: | Cc: | ||
| Guest type: | Linux | Host type: | Linux |
Description
I have been finding that Linux guests seem to lock up when Host I/O cache is disabled when disks are under load (for example when installing system updates). dmesg also shows disk timeouts, and it seems no further disk operations succeed after this point without killing the VM process and restarting.
A log is attached. I'm not sure how to reproduce this reliably, but it seems to happen when I'm installing updates. I have seen this with both Ubuntu and Fedora guests. I will also upload a screenshot shortly with the exact messages, but I seem to have misplaced it for the moment.
I should also note that this is with the VDI nonrotational option turned on and discard=on in the guest Linux OS.
Anything else I can do to help diagnose?
Attachments (2)
Change History (4)
by , 4 years ago
by , 4 years ago
| Attachment: | Disk timeout (SATA, HostIO cache disabled).png added |
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comment:1 by , 4 years ago
NB: VBox.log is from a Fedora system that locked up. The screenshot is from Debian Sid.
comment:2 by , 3 years ago
You already diagnosed it yourself in the ticket description. Your report is a duplicate of older ones which have already established that discard=on (yes, I know, you meant the Linux side, but you enabled the totally undocumented feature in VirtualBox, too) leads to hangs. For example #16795, #16450 and probably more.
Honestly shouldn't be a big surprise that this isn't reliable. Otherwise it would be long documented in the manual and/or enabled by default.
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Kernel messages when disk times out