Somewhere, mdadm is cacheing information. Here is my /etc/mdadm.conf file:
more /etc/mdadm.conf # mdadm.conf written out by anaconda DEVICE partitions MAILADDR root ARRAY /dev/md0 level=raid1 num-devices=4 metadata=0.90 UUID=55ff58b2:0abb5bad:42911890:5950dfce ARRAY /dev/md1 level=raid1 num-devices=2 metadata=0.90 UUID=315eaf5c:776c85bd:5fa8189c:68a99382 ARRAY /dev/md2 level=raid1 num-devices=2 metadata=0.90 UUID=5b017f95:b7e266cc:f17a7611:8b752a02 ARRAY /dev/md3 level=raid1 num-devices=2 metadata=0.90 UUID=4cc310ee:60201e16:c7017bd4:9feea350 ARRAY /dev/md4 level=raid1 num-devices=2 metadata=0.90 UUID=ea205046:3c6e78c6:ab84faa4:0da53c7c
After a system re-boot, here is the contents of /proc/mdstat
# cat /proc/mdstat Personalities : [raid1] md125 : active raid1 sdc3[0] 455482816 blocks [2/1] [U_]
md0 : active raid1 sdd1[3] sdc1[0] sdb1[1] sda1[2] 1000320 blocks [4/4] [UUUU]
md127 : active raid1 sdd3[1] sdb3[0] 971747648 blocks [2/2] [UU]
md3 : active raid1 sdf1[1] sde1[0] 1003904 blocks [2/2] [UU]
md4 : active raid1 sdf3[1] sde3[0] 1948491648 blocks [2/2] [UU]
md1 : active raid1 sda3[1] 455482816 blocks [2/1] [_U]
unused devices: <none>
There are six physical disks in this system:
Disk /dev/sda: 500.1 GB, 500107862016 bytes Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes Disk /dev/sdc: 500.1 GB, 500107862016 bytes Disk /dev/sdd: 1000.2 GB, 1000204886016 bytes Disk /dev/sde: 2000.3 GB, 2000398934016 bytes Disk /dev/sdf: 2000.3 GB, 2000398934016 bytes
I used mdadm --examine /dev/sda1 to find the internal UUID for each of the physical volumes making up these volume groups
/dev/sda1: Magic : a92b4efc Version : 0.90.00 UUID : 55ff58b2:0abb5bad:42911890:5950dfce /dev/sdb1: Magic : a92b4efc Version : 0.90.00 UUID : 55ff58b2:0abb5bad:42911890:5950dfce /dev/sdc1: Magic : a92b4efc Version : 0.90.00 UUID : 55ff58b2:0abb5bad:42911890:5950dfce /dev/sdd1: Magic : a92b4efc Version : 0.90.00 UUID : 55ff58b2:0abb5bad:42911890:5950dfce /dev/sda3: Magic : a92b4efc Version : 0.90.00 UUID : 315eaf5c:776c85bd:5fa8189c:68a99382 /dev/sdc3: Magic : a92b4efc Version : 0.90.00 UUID : 315eaf5c:776c85bd:5fa8189c:68a99382 /dev/sdb3: Magic : a92b4efc Version : 0.90.00 UUID : 5b017f95:b7e266cc:f17a7611:8b752a02 /dev/sdd3: Magic : a92b4efc Version : 0.90.00 UUID : 5b017f95:b7e266cc:f17a7611:8b752a02 /dev/sde1: Magic : a92b4efc Version : 0.90.00 UUID : 4cc310ee:60201e16:c7017bd4:9feea350 /dev/sdf1: Magic : a92b4efc Version : 0.90.00 UUID : 4cc310ee:60201e16:c7017bd4:9feea350 /dev/sde3: Magic : a92b4efc Version : 0.90.00 UUID : ea205046:3c6e78c6:ab84faa4:0da53c7c /dev/sdf3: Magic : a92b4efc Version : 0.90.00 UUID : ea205046:3c6e78c6:ab84faa4:0da53c7c
As you can see, the UUID on the various PVs match the values in the /etc/mdadm.conf file.
My question is What the heck is going on. When I boot the system, I end up with two unexpected, unconfigured volume groups. Where the heck are /dev/md125 and /dev/md127 coming from? They don't appear in /etc/mdadm.conf and if I re-boot they keep coming back. It appears that somewhere mdadm is keeping information. How can I get rid of it so the mdadm.conf file is used.
Harold