[linux-lvm] LVM Partition Dependency

[linux-lvm] LVM Partition Dependency

[pbmonday]

I'm trying to construct an LVM solution with block devices that are not
located in the partition table (becuase they are not a local fixed physical
disk).  I'm curious how deep the dependency on being in the partition goes
with the LVM.

For example, I know the /proc/partitions file is checked during
pvcreate...if I rewrote pvcreate to get around this check would I encounter
other dependencies on actually being a drive partition located on the local
machine later?

Or, if I added my block device to the partitions table, would that be
enough to fulfill all requirements of being a local partition that are
required by the LVM?

Would the problems be only with the user space tools, or would there also
be problems in the kernel module?

Just curious on how far I would have to go to "trick" or "modify" the LVM
to accept something other than a local hard drive partition.

Thank you,
Paul Monday
pbmonday@imation.com

Re: [linux-lvm] LVM Partition Dependency

[Heinz J. Mauelshagen]

Hi Paul.

On Mon, Oct 30, 2000 at 10:01:09AM -0600, pbmonday@imation.com wrote:
> 
> I'm trying to construct an LVM solution with block devices that are not
> located in the partition table (becuase they are not a local fixed physical
> disk). 

Sounds like NBD or friends.

> I'm curious how deep the dependency on being in the partition goes
> with the LVM.

Actually not very deep.

> 
> For example, I know the /proc/partitions file is checked during
> pvcreate...

Yes.
It is done in tools/lib/lvm_dir_cache.c
You need to extend the devdir array.

> if I rewrote pvcreate to get around this check would I encounter
> other dependencies on actually being a drive partition located on the local
> machine later?

It is less a question of beeing local to the machine because there's NBD
support build in anyway. It's more a question of checking for supported
devices in tools/lib/lvm_check_dev.c based on device majors.

> 
> Or, if I added my block device to the partitions table, would that be
> enough to fulfill all requirements of being a local partition that are
> required by the LVM?

That and addiing a new device major to lvm_check_dev.c should do it.

> 
> Would the problems be only with the user space tools, or would there also
> be problems in the kernel module?

The driver only remaps devices and sectors based on tables the userspace
supplies. The only thing it needs to care about that it is a block device ;-)

> 
> Just curious on how far I would have to go to "trick" or "modify" the LVM
> to accept something other than a local hard drive partition.

As i mentioned above: NBD should work.

> 
> Thank you,
> Paul Monday
> pbmonday@imation.com
> 

-- 

Regards,
Heinz      -- The LVM guy --

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Heinz Mauelshagen                                 Sistina Software Inc.
Senior Consultant/Developer                       Bartningstr. 12
                                                  64289 Darmstadt
                                                  Germany
Mauelshagen@Sistina.com                           +49 6151 7103 86
                                                       FAX 7103 96
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Re: [linux-lvm] LVM Partition Dependency

[Heinz J. Mauelshagen]

On Mon, Oct 30, 2000 at 12:02:01PM -0600, pbmonday@imation.com wrote:
> 
> 
> 
> >> I'm trying to construct an LVM solution with block devices that are not
> >> located in the partition table (becuase they are not a local fixed
> physical
> >> disk).
> >Sounds like NBD or friends.
> 
> Yes, I'm actually using ENBD, but, same difference.
> 
> >It is less a question of beeing local to the machine because there's NBD
> >support build in anyway.
> 
> This is interesting...when was this support added to the LVM?

It was already in before 0.8final.

> 
> I'm not having any luck with pvcreate tool shipped with SuSE 6.4 and
> 
> LVM 0.8final.

It should work in 6.4 with NBD and major 43.
Did you run a "pvcreate -d" to figure the reason out?

> I will upgrade my LVM tools, maybe that will do the trick.
> 
> >> Just curious on how far I would have to go to "trick" or "modify" the
> LVM
> >> to accept something other than a local hard drive partition.
> >As i mentioned above: NBD should work.
> I assume you mean NBD should work natively, without any of the changes
> I mentioned to pvcreate?

Exactly.

"pvcreate -d" will help us to analyze what's going on.

> 
> Thanks for your very quick response.
> 

You're welcome :-)

> 
> 
> Paul

-- 

Regards,
Heinz      -- The LVM guy --

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Heinz Mauelshagen                                 Sistina Software Inc.
Senior Consultant/Developer                       Bartningstr. 12
                                                  64289 Darmstadt
                                                  Germany
Mauelshagen@Sistina.com                           +49 6151 7103 86
                                                       FAX 7103 96
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Re: [linux-lvm] LVM Partition Dependency

[Luca Berra]

On Mon, Oct 30, 2000 at 10:52:11PM +0000, Heinz J. Mauelshagen wrote:
> > 
> > I'm not having any luck with pvcreate tool shipped with SuSE 6.4 and
> > 
> > LVM 0.8final.
> 
> It should work in 6.4 with NBD and major 43.
> Did you run a "pvcreate -d" to figure the reason out?

allow me to guess :))))
since nbd is not a partitionable device, the dir_cache entry
is screwed by a bug in pv_get_size.c,
i posted a patch to this list earlier, andreas should have
updated his RPM.

L.


-- 
Luca Berra -- bluca@comedia.it
    Communication Media & Services S.r.l.

Re: [linux-lvm] LVM Partition Dependency

[Heinz J. Mauelshagen]

On Tue, Oct 31, 2000 at 08:30:19AM +0100, Luca Berra wrote:
> On Mon, Oct 30, 2000 at 10:52:11PM +0000, Heinz J. Mauelshagen wrote:
> > > 
> > > I'm not having any luck with pvcreate tool shipped with SuSE 6.4 and
> > > 
> > > LVM 0.8final.
> > 
> > It should work in 6.4 with NBD and major 43.
> > Did you run a "pvcreate -d" to figure the reason out?
> 
> allow me to guess :))))
> since nbd is not a partitionable device, the dir_cache entry
> is screwed by a bug in pv_get_size.c,
> i posted a patch to this list earlier, andreas should have
> updated his RPM.

...and I have it in the 0.9 alpha source :))))

-- 

Regards,
Heinz      -- The LVM guy --

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Heinz Mauelshagen                                 Sistina Software Inc.
Senior Consultant/Developer                       Bartningstr. 12
                                                  64289 Darmstadt
                                                  Germany
Mauelshagen@Sistina.com                           +49 6151 7103 86
                                                       FAX 7103 96
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-