xbd(4) - NetBSD Manual Pages

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XBD(4)                NetBSD/xen Kernel Interfaces Manual               XBD(4)


NAME

     xbd -- Xen frontend paravirtualized block device interface


SYNOPSIS

     xbd* at xenbus?


DESCRIPTION

     The xbd interface forms the frontend part of the paravirtualized drivers
     used by Xen guest domains to have a block device interface.

     From a guest point of view, xbd is similar to a hard disk, and can be
     treated in the very same way regarding partitioning, file systems cre-
     ation and usage, and mounting.  By default, a NetBSD guest domain will
     assume that ``xbd0a'' serves as the root file system.

     When the host is NetBSD, the xbd interface is backed by a xbdback(4)
     interface.  In the XenStore, xbd and xbdback are identified by ``vbd''
     (virtual block device) entries.


DIAGNOSTICS

     xbd%d: using event channel %d  Specifies the event channel used by this
     xbd interface.

     xbd%d: %s MB, %d bytes/sect x %u sectors  Gives the total size of the xbd
     block device, its sector size and total number of sectors.

     xbd%d: WARNING: cache flush not supported by backend  The backend driver
     associated with this xbd device does not support cache flushing opera-
     tion.  This can be problematic for file system operations that require
     cache sync to avoid data loss or corruption.


SEE ALSO

     xbdback(4), xenbus(4), dkctl(8)


HISTORY

     The xbd driver first appeared in NetBSD 3.0.


AUTHORS

     The xbd driver was written by Manuel Bouyer <bouyer@NetBSD.org>.

NetBSD 8.0                      January 8, 2011                     NetBSD 8.0