Re: Which Volume Manager?
On Thu, Nov 07, 2002 at 10:36:45AM -0500, Mark L. Kahnt wrote:
> On Thu, 2002-11-07 at 04:35, Ross Boylan wrote:
> > I am running a 2.4.19 debianized kernel, built from source, and would
> > like to use a volume manager. I would appreciate any advice or
> > clarification of the level of debian support for the different
> > managers. I am trying to run basically a testing system.
> > There seem to be 3 configurations:
> > LVM10 from Sistina (the 1.0 version of LVM)
> > LVM2 from Sistina, beta (2.0 version of LVM)
> > EVMS from IBM
> > I think each additionally requires a separate set of kernel patches to
> > compile, and LVM2 also depends on a "device mapper" (libdevmapper0),
> > which may have a kernel component also.
> > Since LVM2 is beta, missing many features, and seems to have a
> > showstopper bug
> > (http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=163020)--though
> > severity is marked as normal--I'd say it's out.
> > Some comments on one of the debian installer list described EVMS as
> > intriguing but untested; my search of the net seems to show it's well
> > thought of by its few users, but the kernel team doesn't like the
> > internals. The kernel team didn't like LVM version 1 either, and I
> > believe its presence in the development kernels has been terminated
> > with extreme prejudice.
> > EVMS and LVM both seem to be out of the planned 2.6 kernel, while
> > LVM2, or at least some elements, are in
> > (http://www.kernelnewbies.org/status/latest.html). The EVMS team
> > responded to this and the kernel team's comments by deciding on a major
> > rearchitecting of that package
> > (announced 11/5. See
> > http://marc.theaimsgroup.com/?l=linux-kernel&m=103653726515692&w=2).
> > Both EVMS and LVM2 should be able to read LVM volumes.
> > EVMS currently appears to have a richer set of client tools (even a
> > gui interface), and to be a more ambitious project than LVM. This has
> > its good and bad points. I like the positive things its users say
> > about the system and the developers, as well as the apparent maturity
> > and seriousness of the developers in their posts, but am concerned by
> > the relative newness to Linux and the fact that it appears to be
> > another one of these doomed but noble IBM attempts to build software
> > that pluggably adapts to any operating system or requirement.
> > In view of all this, can anyone suggest which, if any, of the volume
> > managers to use right now, and tell me what I need to do to get it
> > working? Info on which way the wind is blowing on debian's choice of
> > volume managers would be highly relevant.
> > On the latter, my suspicion is that for evms I apply kernel-patch-evms
> > and rebuild my kernel, using the available tools packages. I suspect
> > that for LVM I may only need to enable the relevant options in the
> > kernel and rebuild, again using the tools packages. Any confirmation
> > or denial of these theories would be great.
> Last week's LWN (now freely available) is mentioning that LVM2 is
> supposed to be going into the 2.6 kernel, and that EVMS will adjust its
> tools to work with LVM2. Have I missed something since then that says
> that changed? I don't follow the discussions of the kernel developers,
> so that is a possibility.
That report is basically consistent with what I saw, though more
definite that LVM2 is in. I have the impression there is currently no
functional volume manager that goes with the 2.5 kernel, since LVM2 is
a work in progress.
Also, EVMS is adjusting to work with the entire planned kernel, not
just LVM2. I think the LVM2's device mapper and md are both key
technologies they will use and, possibly, modify.
P.S. LWN said it wouldn't be available til the 14th or 15th when I