[linux-lvm] Unable to use metadata.dirs in lvm.conf? (Was: Re: Solving the "metadata too large for circular buffer" condition)

[Andrew Gideon <ag2827189@tagmall.com>]

On Wed, 24 Nov 2010 20:28:11 +0000, Andrew Gideon wrote:

> Finally, there was mention of changing lvm.conf - presumably,
> metadata.dirs - to help make more space.  Once lvm.conf is changed, how
> is that change made live?  Is a complete reboot required, or is there a
> quicker way?

It looks like changes to this file are immediate.  However, I'm having a problem
with metadata being stored "outside" the VG.

I tried:
   * For all PVs in the test VG but one:
      * pvcreate -ff --restorefile /etc/lvm/backup/... --uuid ... --metadatacopies 0  /dev/xvdN1
   * vgcfgbackup
   * cp -p the backup file to the directory I will specify for metadata.dirs in lvm.conf
   * Add the directory to lvm.conf as metadata.dirs

I immediately start seeing "memory" errors from LVM commands.  For example:

	[root@noodle6 tagonline]# vgscan
	  Reading all physical volumes.  This may take a while...
	  Found volume group "TestVG0" using metadata type lvm2
	  Found volume group "guestvg00" using metadata type lvm2
	  You have a memory leak (not released memory pool):
	   [0x83e7848]
	   [0x83e7868]
	  You have a memory leak (not released memory pool):
	   [0x83e7848]
	   [0x83e7868]
	[root@noodle6 tagonline]# 

I then
   * pvcreate -ff --restorefile /etc/lvm/backup/... --uuid ... --metadatacopies 0  /dev/xvdN1
on the final PV that has metadata.  

Now, I cannot see the volume group:

	[root@noodle6 tagonline]# vgdisplay -v TestVG0
	    Using volume group(s) on command line
	    Finding volume group "TestVG0"
	    Wiping cache of LVM-capable devices
	  Volume group "TestVG0" not found
	  You have a memory leak (not released memory pool):
	   [0x8c59ef8]
	   [0x8c55fa8]
	   [0x8c55ed0]
	   [0x8c48aa0]
	  You have a memory leak (not released memory pool):
	   [0x8c59ef8]
	   [0x8c55fa8]
	   [0x8c55ed0]
	   [0x8c48aa0]
	[root@noodle6 tagonline]# 

If I
   * pvcreate -ff --restorefile /etc/lvm/backup/... --uuid ... --metadatacopies 1  /dev/xvdN1
   * vgcfgrestore 
then the volume group is back.  More oddly, vgdisplay -v reports:

  Metadata Areas        2

but, for some reason, the metadata area being used on a separate file system isn't
sufficient or working.

Am I doing something wrong?

This is on CentOS 5.5 386 with:

	[root@noodle6 tagonline]# lvm version
	  LVM version:     2.02.56(1)-RHEL5 (2010-04-22)
	  Library version: 1.02.39-RHEL5 (2010-04-22)
	  Driver version:  4.11.5

Thanks...

	- Andrew