I have a server with openSUSE 13.1 on a single HDD (500 GB WD). The server has information on it and its working properly. Can i create a software RAID1 inserting a second 500 GB WD HDD? How can this be done?
Yes. The software to use is called
mdadm, and I have done exactly what you describe. (In fact I put a 1TB second disk in, and just created an unmirrored partition with the rest of the space; so it can actually be quite flexible.)
Basically you create the raid array with just your current disk. Then you add the new disk to the software array, ask it to copy them over (IIRC you start the system in single-user root mode to do this copy, to make sure no background processes are writing to disk).
For the exact procedure, follow a tutorial; this appears to be the primary one: https://raid.wiki.kernel.org/index.php/Linux_Raid
I do not believe there will be anything Suse specific you need to worry about; just make sure you install mdm from the RPM, and it should create the config and startup files in the correct place. (A google on "suse mdadm" found a youtube tutorial you might also want to take a look at.)
The best way is as Darren Cook mention in his answer; however, the SuSE way is as follows:
Use YaST (
yast disk) to set it up through all of the menus and prompts. I would strongly recommend using hardware RAID (purchasing a RAID card) instead of software RAID.
My personal experience (and I'm no expert in RAID) has been that software RAID always fails.