NAME
virtio_blk – VirtIO Block driver
SYNOPSIS
device virtio_blk
In loader.conf(5): hw.vtblk.no_ident hw.vtblk.%d.no_ident hw.vtblk.writecache_mode hw.vtblk.%d.writecache_mode virtio_blk_load="YES"
In loader.conf(5) or sysctl.conf(5): dev.vtblk.%d.writecache_mode
HARDWARE
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.%d.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.%d.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.%d.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
HISTORY
The virtio_blk driver was written by Bryan Venteicher ⟨[email protected]⟩. It first appeared in FreeBSD 9.0.