Re: (reiserfs) Re: LVM / Filesystems / High availability
Florian Lohoff (flo@quit.mediaways.net)
Thu, 25 Jun 1998 14:39:10 +0200
On Thu, Jun 25, 1998 at 05:16:20AM -0400, Albert D. Cahalan wrote:
> Michael Marxmeier writes:
> > Stephen C. Tweedie wrote:
> >> On Tue, 23 Jun 1998 20:26:14 +0200, Michael Marxmeier <mike@msede.com>
>
> >>> There are two levels of LVM on HP-UX:
> >>
> >>> 1. The basic LVM functionality is to provide a virtual block device
> >>> (logical volumes) and also provides some RAID levels. Resizing of
> >>> filesystem requires unmounting and using the extendfs utility.
> >>
> >> md already provides the ability to do much of this. The question is
> >> whether we need to actually resize existing [virtual] block devices:
> >
> > LVM extends on the capabilities of MD.
> > - MD is limited to block devices whereas LVM is much more flexible
> > to support non-continguous devices as well.
> > - standard administration
> > - the LVM design could more easily extended
> >
> > I would like MD to be replaced by LVM.
>
> MD can provide the real block devices.
>
> LVM can be a user-space abstraction. All your admin tools would
> work in terms of an LVM, perhaps defined in /etc/lvm.conf.
> The kernel filesystem code uses multiple block devices, but you
> don't have to know that.
The LVM already has got functionality for striping AFAIK and everything
else ist just a PE allocation thing and some functions to multiply
PEs ...
All those raid levels will perfectly fit into the LVM. No need for
the MD things then. AFAIK uses Heinz the MD routines to do the
internal things ..
Flo
--
Florian.Lohoff@mediaWays.net +49-5241-80-7085
aka flo@mini.gt.owl.de @HOME +49-5241-470566
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