Software Raid 1 setup

[bsasninja]

I have a disk(1) with all system structure and a backup disk(2).
I would like to add a third disk to the system and make a raid with disk (1).

Is it posible? Which are the steps or if there is a easy how to.

Thanks

 

[DaveUsedToWorkHere]

Your post is a bit vague as it doesn't specify your operating system. Here's a software raid article for rhel based systems: http://www.centos.org/docs/5/html/Deployment_Guide-en-US/s1-raid-config.html