Thanks, now I have someone to interrogate, who seems to have seen these boxes live - if you don't mind ;)
----- Original Message ----- From: Richard Elling <richard.ell...@gmail.com> Date: Monday, May 30, 2011 22:04 > We also commonly see the dual-expander backplanes. > > > According to the docs, each chip addresses all disks on its > backplane, and it seems > > implied (but not expressly stated) that either one chip and > path works, or another. > > For SAS targets, both paths work simultaneously. Does this mean that if the J0 uplinks of backplanes are connected to HBAs in two different servers, both of these servers can address individual disks (and the unit of failover is not a backplane but a disk after all)? And if both HBAs are in a single server, this doubles the SAS link throughput by having two paths - and can ZFS somehow balance among them? > > > So if your application can live with the unit of failover > being a bunch of 21 or 24 disks - > > that might be a way to go. However each head would only have > one connection to > > each backplane, and I'm not sure if you can STONITH the non- > leading head to enforce > > failovers (and enable the specific PRI/SEC chip of the backplane). > > The NexentaStor HA-Cluster plugin manages STONITH and reservations. > I do not believe programming expanders or switches for > clustering is the best approach. > It is better to let the higher layers manage this. Makes sense. Since I originally thought that only one path works at a given time, it may be needed to somehow shutdown the competitor HBA/link ;) > > I am not sure if this requirement also implies dual SAS data > connectors - pictures > > of HCL HDDs all have one connector... > > These are dual ported. Does this mean mecanically two 7-pin SATA data ports and a wide power port, for a total of 3 connectors on the back of HDD, as well as on the backplane sockets? Or does it mean something else? Because I've looked up half a dozen of SuperMicro-supported drives (bold SAS in the list for E2-series chassis), and in the online shops' images they all have the standard 2 connectors (wide and 7-pin): http://www.supermicro.com.tr/SAS-1-CompList.pdf The HCL is rather small, and "other components may work but are not supported by SuperMicro". And to be more specific, do you know if Hitachi 7K3000 series SAS models HUS723020ALS640 (2Tb) or HUS723030ALS640 (3Tb) are suitable for these boxes? Does it make sense to keep the OS/swap on faster smaller drives like a mirror of HUS156030VLS600 (300Gb SAS 15kRPM) - or is it a waste of money? (And are they known to work in these boxes?) > > Hint: Nexenta people seem to be good OEM friends with > Supermicro, so they > > might know ;) > > Yes :-) > -- richard Thanks! //Jim Klimov
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