weird duplicate pv problem

I have an lvm2 volume group composed of about 8 different pvs. Recently, most lvm commmands started displaying errors like below. Not that it is claiming duplicate PVs, but the duplicates are contained in /dev/nbd/*, and I'm not actually using any network block devices. I have NBD comiled into the kernel, and I'm about to compiling a kernel with nbd not compiled in and see if that helps, but it seems extremely odd that lvm would detect duplicate pvs on unused nbd devices.

The effects of the problem (in addition to getting these warnings, are that any change to a lv(resizing, for example), will render that lv inactive or suspended (have seen both), until I do a magic incarnation that involves first "vgcfgrestore" and then "lvchange -a y" on the affected lv. Note that vgcfgrestore does not make the warnings go away, but it does allow the lvchange command to succeed.

Any thoughts? FWIW, I am using devfs, and I'm still curious about a reasonable migration strategy to move an lvm2 setup to non-devfs. Kernel 2.6.0-test11, lvm tools that come with debian sid(lvm version 2.00.05, library version 1.00.05-ioctl-cvs, driver version 4.0.0).

-Tupshin

Found duplicate PV M20svyTZBtuUWDqrlVcwufe0UTwu7bsP: using /dev/nbd/1
not /dev/hdg1
Incorrect metadata area header checksum
Found duplicate PV vnA2QpnmuXZpj5oAFKymumCCEICD0HA1: using /dev/nbd/65
not /dev/hdh1
Incorrect metadata area header checksum
Found duplicate PV cG67YV7KK1Imi8x0sZGl5gpiKXlyXKGV: using /dev/nbd/66
not /dev/hdl1
Incorrect metadata area header checksum
Found duplicate PV cG67YV7KK1Imi8x0sZGl5gpiKXlyXKGV: using /dev/nbd/67
not /dev/hdl1
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/68
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/69
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/70
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/71
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/72
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/73
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/74
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/75
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/76
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/77
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/78
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/79
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/80
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/81
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/82
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/83
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/84
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/85
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/86
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/87
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/88
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/89
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/90
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/91
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/92
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/93
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/94
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/95
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/96
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/97
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/98
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using /dev/nbd/99
not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using
/dev/nbd/100 not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using
/dev/nbd/101 not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using
/dev/nbd/102 not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using
/dev/nbd/103 not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using
/dev/nbd/104 not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using
/dev/nbd/105 not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using
/dev/nbd/106 not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using
/dev/nbd/107 not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using
/dev/nbd/108 not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using
/dev/nbd/109 not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using
/dev/nbd/110 not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using
/dev/nbd/111 not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using
/dev/nbd/112 not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using
/dev/nbd/113 not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using
/dev/nbd/114 not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using
/dev/nbd/115 not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using
/dev/nbd/116 not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using
/dev/nbd/117 not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using
/dev/nbd/118 not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using
/dev/nbd/119 not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using
/dev/nbd/120 not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using
/dev/nbd/121 not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using
/dev/nbd/122 not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using
/dev/nbd/123 not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using
/dev/nbd/124 not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using
/dev/nbd/125 not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using
/dev/nbd/126 not /dev/hdb4
Incorrect metadata area header checksum
Found duplicate PV 4oBUtBXUZ23rcLjA9AHc3XGQLxpjqIxv: using
/dev/nbd/127 not /dev/hdb4
Incorrect metadata area header checksum
Incorrect metadata area header checksum
Incorrect metadata area header checksum
Incorrect metadata area header checksum
Incorrect metadata area header checksum
WARNING: Volume group "lvm_group_1" inconsistent
--- Volume group ---

 VG Name               lvm_group_1
 System ID             PV_IMP(none)1043708474
 Format                lvm2
 Metadata Areas        8
 Metadata Sequence No  49
 VG Access             read/write
 VG Status             resizable
 MAX LV                256
 Cur LV                32
 Open LV               31
 Max PV                256
 Cur PV                8
 Act PV                8
 VG Size               672.97 GB
 PE Size               32.00 MB
 Total PE              21535
 Alloc PE / Size       11546 / 360.81 GB
 Free  PE / Size       9989 / 312.16 GB
 VG UUID               yw5iGA-cA7L-OHCF-iWxJ-rOaR-wg9u-ncQcu6

As I suspected, running a kernel with nbd compiled as a module and not loading it at startup avoids this probem. But this doesn't bring me any closer to an understanding of why lvm would see duplicate pv id's on nbd devices that I never used.

-Tupshin