| 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 9.1 |