Apologies if my terminology is wrong, but I'm new to creating RAID disks.  I'm trying to see if it's possible to control how disks are used in a RAID 10 configuration, because I have drives connected to different SATA controllers and I think I'll get better performance if the mirrored drives are on the same controllers.

 

At the moment I have 2x500GB (Disk1, Disk2) drives connected to controller 1 as my current cache pool (RAID1) giving me 500GB of storage, and 2x250GB (Disk3, Disk4) drives connected to controller 2 via UD in a RAID0 configuration for 500GB of storage with no redundancy. 

 

I've just realised that if I add another 500GB drive (Disk5) I can create a 1000GB RAID10 array i.e. performance and redundancy.  This will also have advantages in my setup as files that are currently copied from the RAID0 to the RAID1, won't be in the future.  I'll also have drives mounted via unRAID rather than UD for more functionality.  Seems a good investment for around £80.

 

What I'd like to do is keep Disk 1 and Disk 2 as one mirrored pair on one controller, and the new Disk 5 being a mirror of Disk 3&4 on the other controller (a bit slower) i.e I want to avoid Disk 1 or 2 on the faster controller being the mirror of Disk3&4, and Disk 5 being a mirror of Disk 1 or 2.

 

Is this possible?  Thanks

17 minutes ago, DZMM said:

Is this possible?

No, you have no say on how btrfs uses the disks, on raid configs it usually writes first to the device with the most available space, then the next one and so on.

Pity, as I was hoping to arrange my disks like this:

 

 

I think I've got another solution though.   Thanks