XBDBACK(4) | Device Drivers Manual (xen) | XBDBACK(4) |
xbdback
—
pseudo-device xbdback
xbdback
interface forms the backend part of the
paravirtualized drivers used by Xen domains to offer a block device interface,
similar to a hard disk. xbdback
interfaces are backed
either by a physical device directly, or an image file mounted through
vnd(4).
All xbdback
interfaces follow the
“xbdbackXiY” naming convention, where ‘X’
represents the guest domain identifier, and ‘Y’ an arbitrary
identifier. This identifier is usually associated to the device node as seen
by the guest using major(3) and
minor(3) numbers. For example,
identifier “769” (0x301) means major 3 and
minor 1, identified as “hda1” under Linux
convention. For NetBSD, the guest device name
specified in the guest configuration file does not matter, and can be chosen
arbitrarily.
A xbdback
interface will appear as a
xbd(4) block device inside a
NetBSD guest domain. In the XenStore,
xbd
and xbdback
are
identified by “vbd” (virtual block device) entries.
xbdback
interface for the
given guest domain, and its size, in bytes.EBUSY
), the device is likely to be already
mounted. It must be unmounted first, as the system will refuse to open it
a second time.xbdback
driver first appeared in
NetBSD 4.0.
xbdback
driver was written by
Manuel Bouyer
<bouyer@NetBSD.org>.
June 7, 2011 | NetBSD 9.4 |