ZFS errors on the array but not the disk.

[Zaphod Beeblebrox]

What does it mean when checksum errors appear on the array (and the vdev)
but not on any of the disks?  See the paste below.  One would think that
there isn't some ephemeral data stored somewhere that is not one of the
disks, yet "cksum" errors show only on the vdev and the array lines.  Help?

[2:17:316]root at virtual:/vr2/torrent/in> zpool status
  pool: vr2
 state: ONLINE
status: One or more devices is currently being resilvered.  The pool will
        continue to function, possibly in a degraded state.
action: Wait for the resilver to complete.
  scan: resilver in progress since Thu Oct 23 23:11:29 2014
        1.53T scanned out of 22.6T at 62.4M/s, 98h23m to go
        119G resilvered, 6.79% done
config:

        NAME               STATE     READ WRITE CKSUM
        vr2                ONLINE       0     0    36
          raidz1-0         ONLINE       0     0    72
            label/vr2-d0   ONLINE       0     0     0
            label/vr2-d1   ONLINE       0     0     0
            gpt/vr2-d2c    ONLINE       0     0     0  block size: 512B
configured, 4096B native  (resilvering)
            gpt/vr2-d3b    ONLINE       0     0     0  block size: 512B
configured, 4096B native
            gpt/vr2-d4a    ONLINE       0     0     0  block size: 512B
configured, 4096B native
            ada14          ONLINE       0     0     0
            label/vr2-d6   ONLINE       0     0     0
            label/vr2-d7c  ONLINE       0     0     0
            label/vr2-d8   ONLINE       0     0     0
          raidz1-1         ONLINE       0     0     0
            gpt/vr2-e0     ONLINE       0     0     0  block size: 512B
configured, 4096B native
            gpt/vr2-e1     ONLINE       0     0     0  block size: 512B
configured, 4096B native
            gpt/vr2-e2     ONLINE       0     0     0  block size: 512B
configured, 4096B native
            gpt/vr2-e3     ONLINE       0     0     0
            gpt/vr2-e4     ONLINE       0     0     0  block size: 512B
configured, 4096B native
            gpt/vr2-e5     ONLINE       0     0     0  block size: 512B
configured, 4096B native
            gpt/vr2-e6     ONLINE       0     0     0  block size: 512B
configured, 4096B native
            gpt/vr2-e7     ONLINE       0     0     0  block size: 512B
configured, 4096B native

errors: 43 data errors, use '-v' for a list