Requirements

• 10TB storage
• current usage is 8.4TB

Options

• (2+2)x 6TB, 12TB raid 10 = 12TB
• (2+4)x 6TB, 24TB raid 6
• (2+4)x 6TB, 18TB raid 10
• (2+2)x 6TB, 3x3TB raid 6

Resources

• ZFS encryption vs ZFS+LUKS

Configurations

• H = Hot
• P = Parity

Rebuild RAID6

• (1H + 2P + 6) x 3TB = 12TB usable out of 33TB

RAID10

• 50% storage efficiency
• vs raid6
  • much faster resilver
  • less load
  • less risk of further failures
• not guaranteed to survive 2 disk failures
  • 4 disks: 33% failure
  • 6 disks: 20% failure
  • n disks: P(fail) = 1/n-1
• each pair should be 1 old and 1 new 6TB drive

ZFS mirror vdev

• LUKS on top requires guest FS (so, ext4 again...)
• LUKS beneath requires individual encryption for each disk (blegh...)
• can stripe across pairs of different sizes (e.g. 4x6TB, 2x3TB = 15TB usable)

Migration Strategy

• duplicate mount of md6-media at /mnt/media
• migrate metadata and config
• unmount md6-media and mount ia/media in its place
• symlink /mnt/media as /mnt/md6-media
• symlink /mnt/home as /mnt/md6-home
• symlink /mnt/systems as /mnt/md6-media/systems