NAME¶
virtio_blk
—
VirtIO Block driver
SYNOPSIS¶
To compile this driver into the kernel, place the following lines in your kernel
configuration file:
device
virtio_blk
Alternatively, to load the driver as a module at boot time, place the following
line in
loader.conf(5):
DESCRIPTION¶
The
virtio_blk
device driver provides support
for VirtIO block devices.
LOADER TUNABLES¶
Tunables can be set at the
loader(8) prompt before
booting the kernel or stored in
loader.conf(5).
- hw.vtblk.no_ident
-
- hw.vtblk.X.no_ident
-
These tunables disable retrieving the device identification string from the
hypervisor either globally or per-device. The default value is 0.
- hw.vtblk.writecache_mode
-
- hw.vtblk.X.writecache_mode
-
These tunables determine the write cache mode globally or per-device. The
mode can changed only if the ConfigWCE feature is negotiated. Set to 0 for
writethrough mode, 1 for writeback mode, and -1 to leave it as-is. The
default value is to leave as-is.
SYSCTL VARIABLES¶
The following variables are available as
sysctl(8)
variables.
- dev.vtblk.X.writecache_mode
-
The write cache mode of the device can be either writethrough (0) or
writeback (1). If the ConfigWCE feature is negotiated, the write cache
mode can be toggled between writethrough and writeback.
SEE ALSO¶
virtio(4)
HISTORY¶
The
virtio_blk
driver was written by
Bryan Venteicher
⟨bryanv@FreeBSD.org⟩. It first appeared in
FreeBSD 9.0.