Quorum active or not?

AIX 5.3 TL7 introduces concurrent quorum changes on a volume group. Prior to that version, the quorum change only becomes active after a varyoff/varyon operation on that specific volume group. This also means that, whever the ODM value is changed, there is no easy way to know whether quorum is currently active or not since lsvg displays the values of ODM attributes, not real-time values.
Fortunately, there is way to figure out whether quorum is active or not. This involves debugging the running kernel using kdb. The procedure to do this is as follows:

- Determine the major number of the volume group in /dev, and convert to the hexadecimal value. F.e. rootvg will always have a major number of 10 (hexadecimal A) and all logical volumes will have a sequential minor number starting at 1.

# ls -al /dev/rootvg
crw-rw---- 1 root system 10, 0 Apr 24 2008 /dev/rootvg

- List the device switch table entry for the volume group, based on the hexadecimal major number, and track the effective address of the volgrp structure in memory (dsdptr)

# echo 'devsw 0xA' | kdb
The specified kernel file is a 64-bit kernel
Preserving 1402949 bytes of symbol table
First symbol __mulh
START END
0000000000001000 0000000003DDF050 start+000FD8
F00000002FF47600 F00000002FFDC920 __ublock+000000
000000002FF22FF4 000000002FF22FF8 environ+000000
000000002FF22FF8 000000002FF22FFC errno+000000
F100070F00000000 F100070F10000000 pvproc+000000
F100070F10000000 F100070F18000000 pvthread+000000
PFT:
PVT:
id....................0002
raddr.....000000000A000000 eaddr.....F200800040000000
size..............00080000 align.............00001000
valid..1 ros....0 fixlmb.1 seg....0 wimg...2
(0)> devsw 0xA
Slot address F1000100101AA500
MAJOR: 00A
   open: 04165624
   close: 04164EC8
   read: 04164738
   write: 04164638
   ioctl: 04162960
   strategy: 04180E9C
   ttys: 00000000
   select: .nodev (00196AE4)
   config: 041588F8
   print: .nodev (00196AE4)
   dump: 04181E68
   mpx: .nodev (00196AE4)
   revoke: .nodev (00196AE4)
   dsdptr: F100010032BA2000
   selptr: 00000000
   opts: 0000012A DEV_DEFINED DEV_MPSAFE DEV_EXTBUF

- Determine the flags attribute of the volgrp structure. The last bit is about quorum (1 -> quorum disabled)

# echo 'volgrp F100010032BA2000' | kdb | grep flags | awk '{print $4}'
00000001