iostat/kernel output for dm devices broken

lsb_release -rd
Description: Ubuntu 10.04.3 LTS
Release: 10.04

apt-cache policy sysstat
sysstat:
  Installed: 9.0.6-2
  Candidate: 9.0.6-2
  Version table:
 *** 9.0.6-2 0
        990 http://archive.ubuntu.com/ubuntu/ lucid/main Packages
        100 /var/lib/dpkg/status

 apt-cache policy linux
linux:
  Installed: (none)
  Candidate: 2.6.32.36.42
  Version table:
     2.6.32.36.42 0
        990 http://archive.ubuntu.com/ubuntu/ lucid-updates/main Packages
     2.6.32.35.41 0
        990 http://archive.ubuntu.com/ubuntu/ lucid-security/main Packages
     2.6.32.21.22 0
        990 http://archive.ubuntu.com/ubuntu/ lucid/main Packages

Firstly I have no /dev/dm* device files and I would expect to have them.

dmsetup ls
36000402002fc827b66970aae00000000 (251, 3)
36000402002fc827b66970aac00000000 (251, 2)
vg1-lvol0 (251, 0)
36000402002fc827b66970aaf00000000 (251, 1)
36000402002fc827b66970aad00000000 (251, 4)
ls -l /dev/dm*
ls: cannot access /dev/dm*: No such file or directory

This is the mapping of paths to /dev/sd
 multipath -ll
36000402002fc827b66970aae00000000dm-3 NEXSAN ,SATABeast2
[size=15T][features=1 queue_if_no_path][hwhandler=0]
\_ round-robin 0 [prio=130][active]
 \_ 0:0:0:2 sdc 8:32 [active][ready]
\_ round-robin 0 [prio=10][enabled]
 \_ 2:0:0:2 sdg 8:96 [active][ready]
36000402002fc827b66970aac00000000dm-2 NEXSAN ,SATABeast2
[size=15T][features=1 queue_if_no_path][hwhandler=0]
\_ round-robin 0 [prio=130][active]
 \_ 0:0:0:3 sdd 8:48 [active][ready]
\_ round-robin 0 [prio=10][enabled]
 \_ 2:0:0:3 sdh 8:112 [active][ready]
36000402002fc827b66970aaf00000000dm-1 NEXSAN ,SATABeast2
[size=15T][features=1 queue_if_no_path][hwhandler=0]
\_ round-robin 0 [prio=130][active]
 \_ 2:0:0:1 sdf 8:80 [active][ready]
\_ round-robin 0 [prio=10][enabled]
 \_ 0:0:0:1 sdb 8:16 [active][ready]
36000402002fc827b66970aad00000000dm-4 NEXSAN ,SATABeast2
[size=15T][features=1 queue_if_no_path][hwhandler=0]
\_ round-robin 0 [prio=130][active]
 \_ 2:0:0:4 sdi 8:128 [active][ready]
\_ round-robin 0 [prio=10][enabled]
 \_ 0:0:0:4 sde 8:64 [active][ready]

So looking at dm-4
iostat /dev/dm-4 /dev/sdi /dev/sde 10 2
Linux 2.6.38-11-server (sf-nfs-red-c02d) 02/12/11 _x86_64_ (8 CPU)

avg-cpu: %user %nice %system %iowait %steal %idle
           0.16 0.00 1.94 3.68 0.00 94.22

Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
sde 59.85 8839.83 8050.23 19180626896 17467347187
dm-4 0.00 0.00 0.00 8704 0
sdi 0.00 0.00 0.00 8208 0

avg-cpu: %user %nice %system %iowait %steal %idle
           0.36 0.00 1.68 0.00 0.00 97.96

Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
sde 15.40 0.00 6813.30 0 68133
dm-4 0.00 0.00 0.00 0 0
sdi 0.00 0.00 0.00 0 0

so dm-4 is not mirroring sde

Looking in /proc/diskstats doesn't look if dm devices are being updated

egrep 'sde|dm-4' /proc/diskstats
   8 64 sde 90651080 89903468 19180626896 1410791480 39203730 114164693 17468206968 366306424 0 274360100 1777314394
 251 4 dm-4 986 102 8704 790 0 0 0 0 0 790 790
root@sf-nfs-red-c02d:/lib/udev/rules.d# egrep 'sde|dm-4' /proc/diskstats
   8 64 sde 90651080 89903468 19180626896 1410791480 39203848 114165149 17468277323 366314084 0 274360470 1777322054
 251 4 dm-4 986 102 8704 790 0 0 0 0 0 790 790