Regression: "Use Host I/O cache" setting seems to be inverted in 5.2 => fixed in SVN/next maintenance
|Reported by:||Michi||Owned by:|
|Component:||virtual disk||Version:||VirtualBox 5.2.6|
|Guest type:||Linux||Host type:||Linux|
I believe that between 5.1 and 5.2 some change led to an inversion of the "Use Host I/O cache" setting.
I mark this bug as critical as people that explicitly disable Host I/O caching to ensure data integrity in case of a power outage may now actually have Host I/O caching enabled and are in danger of loosing data in power outage/reset situations.
Using VirtualBox for testing system installations I activate the Host I/O caching setting to increase performance when installing a lot of RPMs in the virtual machine, particularly because the VDI file on the host resides on a mechanical HDD. When switching from VirtualBox 5.1 to 5.2, I noticed a considerable slowdown.
I measured the slowdown with an ansible playlist that brings a minimal system (installed with Fedora kickstart) to a production level system. The script spends most time on installing RPMs.
Some stats of the RPM installation: Number of RPM packages before: 324 Number of RPM packages after: 1490 Total file size of all RPMs before: 734 MiB Total file size of all RPMs after: 3.9 GiB
It is Fedora (guest) on Fedora (host).
real 7m38.936s user 0m19.646s sys 0m3.937s
real 52m17.548s user 1m22.884s sys 0m17.828s
Installation run on VirtualBox 5.2.6, "Use Host I/O cache" deactivated:
real 10m3.771s user 0m22.089s sys 0m5.119s
And here I confirm that the test version is still affected: Installation run on VirtualBox 5.2.7, "Use Host I/O cache" activated:
real 37m57.730s user 1m13.114s sys 0m15.521s
Installation run on VirtualBox 5.2.7, "Use Host I/O cache" deactivated:
real 11m1.805s user 0m29.377s sys 0m5.790s
Change History (11)
comment:8 by , 5 years ago
|Summary:||Regression: "Use Host I/O cache" setting seems to be inverted in 5.2 → Regression: "Use Host I/O cache" setting seems to be inverted in 5.2 => fixed in SVN/next maintenance|