What do you mean by one chance to re-mirror? Does this mean that if the resilver fails you can't try it again? Is this documented? With ZFS or regular RAID as long as you have one good disk in the mirror you can resilver, is this not the case for BTRFS? If so this is quite disappointing.

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.