XBDBACK(4) | Device Drivers Manual (xen) | XBDBACK(4) |
xbdback
— Xen
backend paravirtualized block device interface
pseudo-device xbdback
The 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.The xbdback
driver first appeared in
NetBSD 4.0.
The xbdback
driver was written by
Manuel Bouyer
<bouyer@NetBSD.org>.
June 7, 2011 | NetBSD 10.99 |