RAID/LVM setup with existing drives
My current setup has 3 hard drives for sharing data. My 250 GB drive is approching full I decided that to get another one. The new drive will be used for the same type of files (video). I have everything organized into folders such as TV, Movies, etc. I would like to add the new drive and make it a seemless as possible. The two drives must be seen as one. I've tried looking around for info on RAID and LVM to find which is best for me. So far they sound extremely similar as to what I would use them for. But, everything I've found leads me to believe that I would have to backup all the data and format the drive to set it up for a RAID/LVM setup. So, is there a way to set up either RAID or LVM wihtout formatting a full 250 GB drive? Also, is there a reason I should choose LVM over RAID or vice versa?