to set up a realcrypt / truecrypt partition, I have used this guide before:
http://altoptions.wordpress.com/2008/01/16...t-howto-part-1/
but this time, I want to use it on a Linux RAID (mdX) setup - the raid setup works fine without realcrypt / truecrypt.

If I follow the guide and create a realcrypt system out of the drive, then either it will stop when trying to make the device into a realcrypt volume, or it will manage to make the volume but then fail to mount it -
realcrypt -l
will list the device and mapper, but mount will show it's not mounted, and the prompt also doesn't come back after typing the realcrypt password...

Is there something special about these /dev/dmX devices?
Should I not try to use them in the same way as /dev/sdaX when making a realcrypt partition?

Normally, you would use /dev/mdx because it's effectively a point to /dev/sdax and /dev/sdbx or whatever disks you are using. Normally, I found that /boot cannot be encrypted, but the rest of it can be but this was on a normal system without introducing raid arrays into the equation.

Hi Ian, thanks for the reply...

Well, I just gave it up in the end.
I did try to make a truecrypt file around the size of the partition, the first try realcrypt told me 'filesystem full'... after 4 hours of chugging... then the second time it didn't work either due to some other reason, forgot why, perhaps I forgot to format before trying to mount the realcrypt drive. In any case, I decided to forego realcrypt/truecrypt on the raid drive/partition. I did create two regular partitions where everything worked fine..

I can only think perhaps it's a limitation with truecrypt/realcrypt in that you cannot do it on raid arrays maybe