I really like the concept of the Drobo, I just don't like the speed. I want the redundancy and easy upgradeability of the Drobo, but faster. I would love to be able to build something on my own. ZFS seems like a good place to start, but it has either upgradeability or redundancy (RAIDZ) but not both.
To clarify, I want to be able to have an array of disks which are expandable by just adding a drive and have redundancy built in.
I found instructions for making zfs act like a Drobo, but they are quite complicated and upgrading is a lot of work. Has anyone automated something like what is described there? Is there a different file system I should be looking at?