Areca Controller disk mapping is incorrect. IPP004 has 24 disk bays arranged in a 6x4 grid.
{{{
+-------+-------+-------+-------+
| disk17| disk18| disk19| disk20|
+-------+-------+-------+-------+
| disk21| disk22| disk23| disk24|
+-------+-------+-------+-------+
| disk13| disk14| disk15| disk16|
+-------+-------+-------+-------+
| disk9 | disk10| disk11| disk12|
+-------+-------+-------+-------+
| disk5 | disk6 | disk7 | disk8 |
+-------+-------+-------+-------+
| disk1 | disk2 | disk3 | disk4 |
+-------+-------+-------+-------+
}}}
  * 2008-01-10T06:45:08 IDE Channel 12 Device Failed  
  * 2008-03-20T00:07:08 IDE Channel 12 Device Failed  
  * 2008-04-07T11:23:04 IDE Channel 12 Device Removed  
  * 2008-04-07T11:38:09 IDE Channel 12 Device Failed  
  * 2008-04-07T15:09:22 IDE Channel 12 Device Failed  
  * 2008-05-08T06:32:55 IDE Channel 6 Device Failed  
  * 2008-05-29T05:44:36 IDE Channel 12 Device Removed  
  * 2008-05-29T11:34:28 IDE Channel 12 Device Removed  
  * 2008-05-29T14:22:27 IDE Channel 12 Device Removed  
  * 2008-05-29T14:43:31 IDE Channel 12 Device Failed  
  * 2008-05-29T14:54:44 IDE Channel 12 Device Removed  
  * 2008-05-29T15:10:57 IDE Channel 12 Device Failed  
  * 2008-05-29T19:59:58 IDE Channel 12 Device Failed  
  * (disk slot 12 has been determined to be broken)
  * 2008-08-20T18:20 (approx) network became unresponsive. notified by nagios. Power cycled by gavin
  * 2008-08-25T20:00 (approx) system became unresponsive. Power cycled by bills
  * 2008-08-30T15:00 (approx) sshd stopped responding.  [wiki:Ipp004-debug-notes-20080830 debug notes]
  * 2008-08-31T22:00 (approx) sshd stopped responding.  rebooted 2008-09-01T06:30
  * 2008-09-02T18:04:33 network became unresponsive (eth0: too many iterations (6) in nv_nic_irq), notified by nagios. power cycled by gavin
  * 2008-09-02T19:00 (approx) ipp004 power cycled due to forcedeth failure
  * 2009-06-15T17:02:53 IDE Channel 11 Reading Error
  * 2010-03-08 Read Error DISK  18 replaced & array rebuilt 
  * 2009-08-24T07:49:39 IDE Channel 17 Device Failed attempted to swap - failed (node 21/node 17 labels exchanged)
  * 2009-08-31T IDE Channel 12 Device Removed (attempt to build disk #12, bad bay, rebuild failed)
  * 2009-09-1 IDE Channel 12 Device Replaced with a 1TB disk - oops.  BUT REBUILDS!  
  * 2010-03-04 IDE Channel 18 Reading Error disc replaced
  * 2010-05-20 IDE Channel 18 Reading Error (Brad attempted to replace but controller states disk #22 pulled instead of 18) Need to rebuild before pulling the disk in disk position 22, which should be 18.(replaced disk #18 2010-05-21T09:34:12)
  * 2010-5-21T09:25:19 IDE Channel 3 Device Failed (replaced 2010-05-21T17:04:44)
  * 2010-06-23T06:02:20 IDE Channel 21 Device Failed (replaced 2010-06-23T14:56:08)
  * 2010-07-21T03:11:02 IDE Channel 15 Device Failed (replaced 2010-07-21T09:55:10)
  * 2010-07-26T09:01:49 IDE Channel 5 Reading Error (replaced 2010-07-26T15:32:54)
  * 2010-07-26T23:03:18 IDE Channel 2 Device Failed (replaced 2010-07-27T10:05:07)
  * 2010-07-28T21:28:44 IDE Channel 14 Device Failed (replaced 2010-07-29T11:32:31)
  * 2010-08-06T08:43:57 IDE Channel 23 Device Failed (replaced 2010-08-06T10:44:25)
  * 2010-08-09T03:11:09 IDE Channel 16 Device Failed (replaced 2010-08-09T09:40:44)
  * 2010-08-19T09:29:35 IDE Channel 19 Device Failed (replaced 2010-08-19T11:26:32)
  * 201-08-23 Multi disk failure [[br]]
    2010-8-23T03:11:01  IDE Channel 1 Device Failed (replaced 2010-08-23T13:20:36) [[br]]
    2010-8-23T04:11:42  IDE Channel 24 Device Failed (replaced 2010-08-24T10:45:15)
  * 2010-08-27T07:09:32 IDE Channel 4 Device Failed (replaced 2010-08-27T14:01:40)
  * 2010-9-9  7:27:1 Controller#1(PCI) IDE Channel 20 Device Failed
  * 2010-9-9  16:40:21 Controller#1(PCI) IDE Channel  9 Device Failed
  * 2010-10-06T20:16:44 IDE Channel 24 Device Failed (replaced 2010-10-07T21:03:04)
  * 2010-10-06T20:46:51 IDE Channel 23 Device Failed (replaced 2010-10-07T11:56:52)