I have a linux software RAID 5 array, made up of 5 x 3 TB drives, giving me roughly 12 TB in total. I want to replace the disks with newer 8 TB drives, but since these are still quite expensive, I would like to start with 3 drives only for now, giving me a total of 16 TB space. This would allow me to later add more 8 TB drives to grow the size of my array as needed.
Now, I know it's possible to replace all disks with larger disks. I also know it's possible to rebuild the array with fewer disks, if you have enough disk space. The problem is, my array is 95% full, which is my primary reason for switching to larger disks in the first place. Since I don't have enough disk space to first rebuild the array with fewer (3 TB) disks, is there any way I can rebuild my current 12 TB (5 x 3 TB) RAID 5 array as a 16 TB (3 x 8 TB) RAID 5 array without losing data?