When you create the volume, you are asked which are primary disks. Select them at that point.

If you first give the disks SoftRAID "disk labels", it will help identify the ones you want as primary.

E.g. if I have some newer drives and some older, and I want to make sure that the RAID 0 is matching old or new drives, then the RAID 1 is a mirror of new drives to old drives?

Sorry no. Lite only supports 1 and 0.

You would have to settle for two independent Mirror volumes.

Yes, SoftRAID supports RAID 1+0, I was commenting on how to "convert". If you can backup and create it, then absoutely, we support this.

The only way we can make it easy is if you create a RAID 0 volume to start with, then convert to RAID 10.

We do not support RAID 0+1, so you cannot do this with Mirrors.

One idea is create another 12TB mirror, and if one is the backup to the other, use a program like Carbon Copy Cloner to schedule regular backups.

we bought SoftRaid recently and we have 2 disks with 12TB each in RAID 1 made in SOFTRAID.

in the near future we will buy another 2 disk with 12 tb or more.

and I have a question, a big one for me: how can I put the two disks to make 24 tb of disk space and the another two in mirror of those 2 disks without lose the data or there is no way?

It is not, at least not in my testing. Writes on RAID 5 are near 3 disks of 4 disks speed. RAID 1+0 is closer to 50% theoretical 4 disk speed.