Did you notice that the official description of RAID-1 is "Mostly working"? Are you aware if one of your drive fails, you have one chance to re-mirror it, before the remaining drive can no longer be mounted read-write and you need to dump the filesystem and re-create from scratch?
There's a reason my server is running ZFS on FreeBSD. I also love jails, which let me have as many virtual servers as I want without any virtualization overhead.
It's documented on the status Wiki. RAID 1 is "mostly working". If a mirror drops to having one disk, you can mount it once as a read-write volume (required for resilvering); after that, you have to trash it and start again.
It might be an inconvenient restriction, but when a drive fails I'm already happy that there will be no data loss.