This could be caused by the following:


  1. You have a bad AAMUX adapter (AAMUX allows dual port access to the single ported SATA drive)
  2. You have a bad PHY/Cable coming from the RAID Head to the JBOD
  3. There is a mismatch in the controller code set i.e. Software, Firmware or Boot loader (these must all match)
  4. Memory module is different capacity on 1 of the 2 controllers (Apple Promise SKU ships with 2Gig Modules)


To better understand the problems please check each respective controller from the RJ11 to RS232 connector via HyperTerminal (open a session for each controller in question), each controller will allow you to monitor it individually. Once you are connected query the event logs. Example: event –l nvram and event commands will get you a detailed rundown of why the X partner controller is maintenance mode:


Additional information pertaining to issue 1 and 2 above:

Assuming issue 1 or 2 is the case the following will help you understand the fail over condition resulting in maintenance mode:


This is the expected result when running Active/Active or Active/Passive config. The rule is the following:


Ex10 RAID Dual Controllers must see all PDs on the Dual controller JBODs in order to maintain cache coherency between the 2 RAID head controllers, both controllers must see all

PDs (dual ported SAS or SATA with AAMUX). If 1 of the paths from the RAID head to the JBOD fails, 1 of the 2 controllers should fail over and the remaining active controller

Should continue to have access to the remaining path on the JBOD.

In an Active/Passive configuration the surviving controller becomes the Active controller.


The attached diagram does not depict the JBOD paths how ever the concept is similar to that of dual path to the PD. If a path from the RAID Head to the JBOD is broken or a path from PD to the RAID Head is broken the end result should be access via the respective remaining active RAID controller having access to the LDs (logical disk array) in question through remaining path.



If you are in need of additional assistance please contact technical support and reference this article.  

Essential information to provide to support:


  1. Save configuration report from WebPam Pro E or CLI using the “export” command (try ? export)
  2. Sequence of events
  3. Apple users please provide your system profiler logs