need to remove md0 from root.
 

I have an Ubuntu server 64 with md0 raid on root.

/dev/md0 on / type ext3 (rw,relatime,errors=remount-ro)

#mdadm --detail /dev/md0:
/dev/md0:
Raid Level : raid1
Array Size : 75208192 (71.72 GiB 77.01 GB)
Used Dev Size : 75208192 (71.72 GiB 77.01 GB)
Raid Devices : 2
Total Devices : 2
Preferred Minor : 0
Persistence : Superblock is persistent
Update Time : Mon Aug 31 10:07:44 2009
State : clean
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
UUID : c5993f75:db028d92:3f29da55:bf6dcaf9
Events : 0.4632
Number Major Minor RaidDevice State
0 8 1 0 active sync /dev/sda1
1 8 17 1 active sync /dev/sdb1


I need to remove this to run vmware converter (doesn't like md0).
I can't kill the raid because I am mounted on root.

I know cfdisk, grub, fstab and /etc/mdadm/mdadm.conf are involved but not quite sure how to proceed. I have backed up the whole system.

Well, if you've got '/' raided, but you want to get rid of the raid, I reckon you need to boot off the installation media, and at text prompt type

linux rescue

You can then proceed to fdisk the HDDs. Remove the fstab and mdadm.conf entries, change the partition types to 83 (std Linux). You'll need to ensure you still have a swap partition (type 82). Update the fstab to match.
http://tldp.org/HOWTO/Partition/fdisk_partitioning.html