On Nov 11, 2007 4:17 PM, Adam Hamsik <haaaad@gmail.com> wrote:
>
> On Nov,Sunday 11 2007, at 12:36 PM, Alistair Crooks wrote:
>
> > On Sun, Nov 11, 2007 at 11:35:45AM +0100, Markus Kolb wrote:
> >> Hi,
> >>
> >> I am thinking of switching to NetBSD.
> >> But I need a Logical Volume Management solution for resizing
> >> partitions
> >> and at least expanding the fs on them and I can't find any up-to-date
> >> information related to this.
> >> - Vinum is removed
> >> - ccd seems to only concatenate different physical disks
> >> - dk wedges seem to be for partitioning big disks or have I
> >> misunderstood?
> >>
> >> If there is anything with PV, PVGroups, LVGroups and LVolumes
> >> possible
> >> how is it called in NetBSD?
> >
> > Yes, vinum was removed because it was not really being maintained, and
> > had some bitrot problems.  ccds will span across multiple physical
> > disks, but isn't the dynamic volume manager that you're looking for.
> >
> > I don't want to try to speak for mycroft, but my understanding of
> > his idea of wedges was that they are just simple things, which use
> > the strategy functionality to route requests to different areas
> > on the block device(s). Something crafted on top of this could provide
> > a nice, light volume manager.
>
> Yes, that's absolutely true. NetBSD wedges provides linear disk blocks
> mapping same as Linux md. IMO it should be not so hard to write simple
> volume manager for NetBSD on top of wedges. There are 3-4 options how
> to do it:
>
> 1)use this years SOC code from ZFS port. I don't know if this code is
> in useable state.
>    if not it would be good give more effort at this.
>
> 2)port Linux libdevmapper and lvm2 tools to netbsd on top of our
> wedges with some support. I think that this way we keep GPL out of
> kernel and we can use IMO really good linux lvm NetBSD volume manager.
> Intro to Linux Lvm internals [2].
>
> 3) write tools + wedge device library from scratch
>
> I prefer 2 because of
>
> Pros
>
> a) well tested code
> b) was already done [1]
> c) I think that linux LVM is better than nothing.
>
> Cons
>
> a) add GPL stuff to netbsd base system :(
> b) too much people here hate Linux and Linux stuff :).
>
> >
> > In general, though, you're right - volume management is something we
> > need to do better.  Whether that's by gobbing the disks altogether in
> > a pool a la ZFS is something we want to do (and I should imagine the
> > security types would have a view on that), or by going the more
> > traditional route with volume management (see the wedges route above),
> > we need to start looking into this more fully. Especially as our
> > iSCSI initiator (plug, plug) now exists and works well.
> >
> > I'd be really interested in talking about this, though it might be
> > better hosted on tech-kern.
> >

4) Re-port vinum userland using weges or get involved with gvinum and
implement it on top of wedges.  (wvinum?)