MD1000 connected with two SAS cables in unified mode

[Jeff Ewing]

>From what I understand of the MD1000 EMMs, there is failover, but only
for the management communications to the chassis, there is no data path
failover.. so losing the active EMM/connection will result in the PERC
needing to re-init (host reboot). This limitation is determined by the
PERC..
> 
> Maybe anyone else who's done this before can comment on it's success..
> 

I had a spare MD1000 so I performed some data path tests.

* Both cables connected in unified mode. 

  The primary path was disconnected.

  - The data was inaccessible.

* Rebooted 

  - The data was accessible down the alternate path.

* Shutdown, reconnected the primary cable and restarted. 

   -The data was accessible (although the RAID array went into 
    a rebuilding state)


For me this appears to provide the required path redundancy (using
a reboot). A reboot is an acceptable cost compared with organizing
onsite technicians at the Data Centre in the case of a path failure.

Jeff