After a Western Digital sale I managed to get my hands on a decently sized HDD in preparation for a NAS I'm gonna build. The plan was to use OpenBSD and a logical volume manager so that I could just throw all disks in a pool and easiy add more when I have more drives, but that is apparently something OpenBSD lack. Instead, I found that NetBSD has a port of the Linux LVM2 tools. Neat! But when it comes to redundancy I'm still a bit miffed. A probable general LVM question, but I don't know if the NetBSD port is 1:1.

I can't setup a good redundacy with the drives I have currently — 6TB + 2x 1TB + 4TB. Is it possible to configure redundacy when I have the drives for it, or must this be done during initial LVM configuration?

When I have multiple drives in a pool, which are the actual data written to. Are they all written to ala RAID0, or is only one drive in use until it's filled up? I presume this is configurable? I'm surprised I haven't found much on this, but it might just be a case where I don't know what to search for.