OpenBSD manual page server

Manual Page Search Parameters

MOUNT_VND(8) System Manager's Manual MOUNT_VND(8)

mount_vndmount vnode disks

mount_vnd [-k] [-K rounds] [-o options] [-S saltfile] [-t disktypeimage vnd_dev

mount_vnd works similarly to vnconfig(8), but it provides an interface that can be used by the fstab(5) infrastructure, so that an image file can be configured to a device vnd_dev while booting.

For fstab(5) lines with type “ffs”, the “noauto” option must be set to prevent a mount(8) of the FFS partitions before the necessary vnd devices are configured. Also, the “fs_passno” field has to be set to 0 to prevent fsck(8) from checking the file system for the same reasons.

mount_vnd is invoked by mount(8) when using the following syntax:

mount [options] -t vnd image vnd_dev

The options are as follows:

rounds
Associate an encryption key with the device. All data will be encrypted using the Blowfish cipher before it is written to the disk. The user is asked for both a passphrase and the name of a salt file. The salt file can also be specified on the command line using the -S option. The passphrase and salt are combined according to PKCS #5 PBKDF2 for the specified number of rounds to generate the actual key used. rounds is a number between 1000 and INT_MAX. DO NOT LOSE THE SALT FILE.
Associate an encryption key with the device. All data will be encrypted using the Blowfish cipher before it is written to the disk.
options
Options are specified with a -o flag followed by a comma separated string of options. See the mount(8) man page for possible options and their meanings.

At the moment, -o is only here for compatibility reasons, but no use is made of supplied options.

saltfile
When -K is used, specify the saltfile.
disktype
Specify a disktype entry from the disktab(5) database. The vnd_dev will have the sector size, sectors per track, and tracks per cylinder values of the specified disktype. The defaults are 512-byte sectors, 100 sectors per track and 1 track per cylinder.

/dev/{,r}vnd*
 

An example fstab(5) entry is:

/tmp/cryptimg /dev/vnd0c vnd rw,noauto,-k       0 0
/dev/vnd0a   /mnt        ffs rw,noauto          0 0

Mounting images during the first pass of fsck(8) and mount(8) is not possible, because the image to be configured to a vnd itself resides on a file system that first has to be checked and mounted.

vnd(4), disktab(5), fstab(5), mount(8), swapon(8), umount(8)

The mount_vnd command first appeared in OpenBSD 4.2.

April 25, 2019 OpenBSD-current