[OpenIndiana-discuss] HBA failover

[Sebastian Gabler]

Hi,

it occured to me that obviously some ZFS Storage systems only feature a 
single SAS HBA, including the ZFSSA 7320. At least, as far as I understand.
 From what I saw in the 7320 documentation, each of the two HBA ports is 
connected to each of the two ports of a shelf, which should protect from 
the failure of a single cable, SAS Expander or drive controller (using 
dual ported drives). My understanding is that this topology is drawing 
upon MultiPath. But that still should make the HBA a SPOF, shouldn't it? 
As HBAs are a quite cheap commodity, I wonder why I even don't see a 
secondary HBA as an option for SUN ZFSSAs, or other appliances like the 
Netgear ReadyNas.

Thanks for any hints on how to exclude the HBA as a SPOF without using a 
cluster.

BR,

Sebastian