'Solid State Disk' setting not detected by Linux guest => fixed in SVN

[Jim Avera]

If the "Solid State Disk" check-box is checked for a VM's (vdi) disk, a Linux guest still thinks it is a rotational disk. This prevents the guest OS from issuing Trim commands, etc. The client is running Ubuntu 13.04, kernel 3.8.0

The actual physical disk in the host is in fact an SSD (though that should not matter).

STEPS TO REPRODUCE:

1. Install Ubuntu 13.04 in guest
2. In Settings->Storage->Controller:SATA->xxx.vdi, check the "Solid-state drive" box.
3. Start the guest and open a terminal window
4. Cat /sys/block/sda/queue/rotational

Actual results: 1

Expected results: 0

The same Ubuntu system correctly detects SSDs on bare metal, so VirtualBox must be (not) doing something which prevents the guest from recognizing the SSD designation.

I will attach the host Log file and a copy of the output from "dmesg" in the guest showing detection of /dev/sda

[Jim Avera]

FWIW, the linux kernel may expect SSDs to report a rotational speed of 1 RPM.

See ​http://lxr.linux.no/#linux+v3.10.5/include/linux/ata.h#L914
in function ata_id_is_ssd()

[aeichner]

Thanks for the report. We already report a rotational speed of 1 but newer Linux kernels requires at least ATA major version 7 to evaluate this field. Will be fixed in the next maintenance release.

[Frank Mehnert]

Fix is part of VBox 4.3.2.