Problems with setting up raid1 with mdadm on slackware
 

hello people I am having problems setting up raid1 with the mdadm tool. I tried the software howto to build a raid1 with mk raid but it didn't work also so I tried mdadm and it worked, but after that I realised that i am using incompatible hardware and I changed my HDDs ( Maxtor) with Western Digital. So now I have two 320G Western Digital HDDs and I am doing the same thing as before but the array just doesn't wants to be created. I've read and googled..... but nobody seems to have this kind of problem...
I just want to set up mirroring mode for the two disks.

Device Boot Start End Blocks Id System
/dev/sda1 * 1 38661 310544451 83 Linux
/dev/sda2 38662 38913 2024190 5 Extended
/dev/sda5 38662 38913 2024158+ 82 Linux swap

Device Boot Start End Blocks Id System
/dev/sdb1 * 1 38661 310544451 83 Linux
/dev/sdb2 38662 38913 2024190 5 Extended
/dev/sdb5 38662 38913 2024158+ 82 Linux swap

when I type in the next command

mdadm --create --verbose /dev/md0 --level=1 --raid-devices=2 /dev/sda1 /dev/sdb1


the following message comes out and I am stuck.....

mdadm: /dev/sda1 appears to contain a reiserfs file system
size = 310544448K
Continue creating array? yes
mdadm: ADD_NEW_DISK for /dev/sda1 failed: Invalid argument

I just cannot find a solution to the problem..... I would be pleased if somebody can help me out with this....