[linux-lvm] N00b Question: Logical Volume without a Logical Volume Group ?

Dan White ygor at comcast.net
Tue Nov 1 19:51:21 UTC 2011

----- Digimer <linux at alteeve.com> wrote:
> On 11/01/2011 03:13 PM, Dan White wrote:
> > ----- Digimer <linux at alteeve.com> wrote:
> >> On 11/01/2011 02:39 PM, Dan White wrote:
> >>> Is a logical volume group necessary before one can start making mountable partitions ?
> >>>
> >>> I'm trying to work with a SAN.  We were allocated a 10Gb LUN to "play" with. Another admin created a logical volume on the LUN and then made a single partition out of the logical volume.  The flow I am familiar with from Red Hat's GUI is to first make a logical volume group, then make partitions in the group that I can adjust in size as necessary.
> >>>
> >>> Are both workflows valid ?
> >>
> >> LVs must be created from VGs.
> >>
> > 
> > I agree.  Got a documentation reference I can use for backup ?
> man lvcreate? Not being flippant, but the 'VolumeGroupName' is a
> required value. :)
> Also from the man page;
>        lvcreate creates a new logical volume in a volume group  (  see vgcre-
>        ate(8), vgchange(8) ) by allocating logical extents from the free  phys-
>        ical extent pool of that volume group.  If there are  not  enough free
>        physical  extents  then  the  volume  group can be extended ( see vgex-
>        tend(8) ) with other physical volumes or by reducing  existing logical
>        volumes  of this volume group in size ( see lvreduce(8) ). If you spec-
>        ify one or more PhysicalVolumes, allocation of physical extents will be
>        restricted to these volumes.
>        The second form supports the creation of snapshot logical volumes which
>        keep the contents of the original logical volume for backup purposes.

Many thanks.  Not at all flippant.  Direct and informative.

“Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us.”
Bill Waterson (Calvin & Hobbes)

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