The GENERIC kernel does not contain
vinum. It is possible to build a
custom kernel which includes vinum, but
this is not recommended. The standard way to start
vinum is as a kernel module.
kldload(8) is not needed because when gvinum(8)
starts, it checks whether the module has been loaded, and if it
is not, it loads it automatically.
vinum stores configuration
information on the disk slices in essentially the same form as
in the configuration files. When reading from the
configuration database, vinum
recognizes a number of keywords which are not allowed in the
configuration files. For example, a disk configuration might
contain the following text:
volume myvol state up volume bigraid state down plex name myvol.p0 state up org concat vol myvol plex name myvol.p1 state up org concat vol myvol plex name myvol.p2 state init org striped 512b vol myvol plex name bigraid.p0 state initializing org raid5 512b vol bigraid sd name myvol.p0.s0 drive a plex myvol.p0 state up len 1048576b driveoffset 265b plexoffset 0b sd name myvol.p0.s1 drive b plex myvol.p0 state up len 1048576b driveoffset 265b plexoffset 1048576b sd name myvol.p1.s0 drive c plex myvol.p1 state up len 1048576b driveoffset 265b plexoffset 0b sd name myvol.p1.s1 drive d plex myvol.p1 state up len 1048576b driveoffset 265b plexoffset 1048576b sd name myvol.p2.s0 drive a plex myvol.p2 state init len 524288b driveoffset 1048841b plexoffset 0b sd name myvol.p2.s1 drive b plex myvol.p2 state init len 524288b driveoffset 1048841b plexoffset 524288b sd name myvol.p2.s2 drive c plex myvol.p2 state init len 524288b driveoffset 1048841b plexoffset 1048576b sd name myvol.p2.s3 drive d plex myvol.p2 state init len 524288b driveoffset 1048841b plexoffset 1572864b sd name bigraid.p0.s0 drive a plex bigraid.p0 state initializing len 4194304b driveoff set 1573129b plexoffset 0b sd name bigraid.p0.s1 drive b plex bigraid.p0 state initializing len 4194304b driveoff set 1573129b plexoffset 4194304b sd name bigraid.p0.s2 drive c plex bigraid.p0 state initializing len 4194304b driveoff set 1573129b plexoffset 8388608b sd name bigraid.p0.s3 drive d plex bigraid.p0 state initializing len 4194304b driveoff set 1573129b plexoffset 12582912b sd name bigraid.p0.s4 drive e plex bigraid.p0 state initializing len 4194304b driveoff set 1573129b plexoffset 16777216b
The obvious differences here are the presence of
explicit location information and naming, both of which are
allowed but discouraged, and the information on the states.
vinum does not store information
about drives in the configuration information. It finds the
drives by scanning the configured disk drives for partitions
with a vinum label. This enables
vinum to identify drives correctly
even if they have been assigned different UNIX® drive
IDs.
Gvinum always features an
automatic startup once the kernel module is loaded, via
loader.conf(5). To load the
Gvinum module at boot time, add
geom_vinum_load="YES" to
/boot/loader.conf.
When vinum is started with
gvinum start,
vinum reads the configuration
database from one of the vinum
drives. Under normal circumstances, each drive contains
an identical copy of the configuration database, so it
does not matter which drive is read. After a crash,
however, vinum must determine
which drive was updated most recently and read the
configuration from this drive. It then updates the
configuration, if necessary, from progressively older
drives.
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