Is there any NAS software that just lets you add disks whenever you want, while using them for redundancy if they aren't full? I wish something was as easy as adding another disk and having the redundancy go up, then removing a disk and having the redundancy go down.
If you just want a mirror, that's easy (I like ZFS but any software RAID should let you add/remove mirrored disks easily). If you mean mirror until it's full then automatically convert to striped, I don't think anyone does that and I don't think anyone would want that, because people who care enough about protecting their data to use a mirror don't want it to automatically stop being a mirror.
