Hi,
I have a Software RAID 1 with Debian lenny (2.6.26) on the top if two
1GB RAID disks (Promise SATA300 TX2). I build three MDs (all RAID1) with
the following commands:
# mdadm --create /dev/md0 --verbose --level=1 --raid-devices=2 /dev/sda1
/dev/sdb1
# mdadm --create /dev/md1 --verbose --level=1 --raid-devices=2 /dev/sda2
/dev/sdb2
# mdadm --create /dev/md2 --verbose --level=1 --raid-devices=2 /dev/sda3
/dev/sdb3
(md0 = Linux root, md1 = data (LVM), md2=swap)
Finally, I saved the configuration with:
# mdadm --examine --scan >> /etc/mdadm/mdadm.conf
# cat /etc/mdadm/mdadm.conf
[...]
ARRAY /dev/md0 level=raid1 num-devices=2
UUID=a17a69b8:8fffe883:f742d439:f75daca2
ARRAY /dev/md1 level=raid1 num-devices=2
UUID=97b4ff9d:246a656e:27cc7924:96506d18
ARRAY /dev/md2 level=raid1 num-devices=2
UUID=b9b6b4d8:ad052c30:dde8335f:840c6bd3
Well, everything worked fine.
But then I wanted to test my SATA RAID and did the following:
1.) Just plugged off one drive (sda)
2.) MDs were in the [_U]-state (/proc/mdstat)
3.) I made an SCSI bus-rescan
Now I wanted to readd the the "failed" drive:
4.) plugged in the drive again
5.) I made an SCSI bus-rescan
6.) the drive appeared as sdd
7.) Removed the failed drives:
# mdadm --manage /dev/md0 --remove failed
# mdadm --manage /dev/md1 --remove failed
# mdadm --manage /dev/md2 --remove failed
8.) added the new (old) ones:
# mdadm --manage /dev/md0 --add /dev/hdd1
# mdadm --manage /dev/md1 --add /dev/hdd2
# mdadm --manage /dev/md2 --add /dev/hdd3
The MDs were rebuilt successfully and now I have [UU]-states again.
But suddenly the UUIDs have changed! In my optinion this should not
happen because I did not recreate the MDs! I just removed and added
devices. As you can see, the UUID changed compared to the output above:
# mdadm --examine --scan
ARRAY /dev/md0 level=raid1 num-devices=2
UUID=ecd91936:b1a55e83:84db6932:6eb15673
ARRAY /dev/md1 level=raid1 num-devices=2
UUID=97b4ff9d:246a656e:27cc7924:96506d18
ARRAY /dev/md2 level=raid1 num-devices=2
UUID=8e413e87:bd062cc3:82a1dfb2:c7b8d31a
The very vers strange thing: Only the UUIDs from md0 and md2 changed!
The first question: Why did this happen? Should this ever happen? What
went wrong? Is this a bug?
The second question: Should I rewrite the mdadm.conf with the new UUIDs?
Regards,
Peter
--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
