Hello.
I have several systems (CentOS 3 and CentOS 4) with software raid and I've observed a difference in the raid state:
In CentOS 3 systems we find that mdadm --detail /dev/md* show: .............. Version : 00.90.00 Creation Time : Fri Apr 16 14:59:43 2004 Raid Level : raid1 Array Size : 20289984 (19.35 GiB 20.78 GB) Device Size : 20289984 (19.35 GiB 20.78 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 5 Persistence : Superblock is persistent
Update Time : Thu Apr 20 15:52:50 2006 State : dirty, no-errors <--------------------------------------------------- RAID STATE Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0
Number Major Minor RaidDevice State 0 33 7 0 active sync /dev/hde7 1 34 7 1 active sync /dev/hdg7 UUID : 232294aa:45bd9dea:c62face1:2fbf7a60 Events : 0.38 ..........................................
while in CentOS 3 systems we find: .................. Version : 00.90.01 Creation Time : Wed Feb 15 10:13:41 2006 Raid Level : raid1 Array Size : 76051584 (72.53 GiB 77.88 GB) Device Size : 76051584 (72.53 GiB 77.88 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 1 Persistence : Superblock is persistent
Update Time : Sun Apr 23 12:48:42 2006 State : clean <------------------------------------------------------- RAID STATE Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0
Number Major Minor RaidDevice State 0 8 1 0 active sync /dev/sda1 1 8 17 1 active sync /dev/sdb1 UUID : 35c88d0d:0a9b5ba5:78a32da7:5d5cb1ec Events : 0.251478
..................
Which is the difference between dirty and clean state? Both systems work fine.