On Mon, Jun 17, 2013 at 3:12 PM, Sebastian Gabler <[email protected]>wrote:
> 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. > My experience here is that the ports on HBAs are independent, and fail independently. (Don't think I've had a SAS HBA fail on me, but I've had several failures of SCSI and FC parts over the years.) Which means that the physical HBA is less of a SPOF than you might think. As others have noted, there are plenty of others. The one case where using multiple HBAs makes sense is if you can hot-swap the card, because then you can replace the failed one while leaving the good one running. But that's not all that common with current commodity hardware. -- -Peter Tribble http://www.petertribble.co.uk/ - http://ptribble.blogspot.com/ _______________________________________________ OpenIndiana-discuss mailing list [email protected] http://openindiana.org/mailman/listinfo/openindiana-discuss
