EVMS, LVM, LVM2, XFS, ext3 on FC3

David Kewley kewley at cns.caltech.edu
Tue Oct 5 21:31:44 UTC 2004


Alan Cox wrote on Tuesday 05 October 2004 10:03:
> On Tue, Oct 05, 2004 at 01:01:49PM -0400, Neal D. Becker wrote:
> > > Is there a good reason to use LVM or LVM2 rather than EVMS?  Is
> > > there a reason EVMS isn't included in FC?
> >
> > IIRC LVM was accepted by kernel developers over EVMS, which quietly
> > accepted this decision.
>
> Indeed. EVMS kernel space is dead. Linus rejected it for the device
> mapper layer. Fedora tracks upstream so EVMS is not in, never having
> made upstream.

Interesting, I didn't know that, but it makes sense given what I've seen 
in the various projects.

> EVMS userspace as I understand it is still being developed but using
> the device mapper.

Right.  Best I can tell, there are no 2.6.8.1 kernel patches required by 
EVMS for the great majority of functionality.  Most of the useful 
functionality is provided in userspace, building on DM as shipped in 
the stock kernel.

There are a couple of optional 2.6.8.1 kernel patches you can apply to 
get extra EVMS functionalilty.  To get EVMS bad block relocation, you 
need to apply a patchset from the DM project's "unstable" patch 
collection, plus a DM patch shipped with EVMS.

To have EVMS manage some partitions on a disk, while allowing the normal 
kernel mechanisms to manage other partitions on that disk, you have to 
apply an EVMS-supplied patch that backs out the bd-claim-whole-disk 
patch that was applied (I think) in kernel 2.6.0-test4.  Most people 
probably either don't want this functionality (keep your kernel-managed 
system disks separate from your data-dump disks), or can work around it 
without applying the back-out patch.

David




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