In my experience the mass market HBAs and RAID cards typically do support only 8 or 16 drives. For the internal variety in a standard rack-mount server you'll usually see either 2 or 4 iPass cables (each of which support 4 drives) connected to the backplane. The marketing material you've referenced has a white lie in it: supporting more than 16 drives on a single card is very likely only possible with an additional SAS expander board. I believe Supermicro does sell some pre-configured systems with such hardware, but expect the throughput to fall through the floor if you use such hardware. Bottom line: the Supermicro application engineer knows what he's talking about. On Sun, Aug 30, 2015 at 1:13 AM, Adrian Sevcenco <Adrian.Sevcenco at cern.ch> wrote: > Hi guys! Unfortunately there is no offtopic list but the subject > is somehow related to centos as the OS is/will be centos :) > So, under this thin cover i ask : > Is it possible that for a SAS controler like LSI 3008 that in specs > says that : "This high-performance I/O controller supports T-10 > data protection model and optical support, PCIe hot plugging, > and up to 1,000 connected devices" in a vendor implementation > (motherboard integrated) to support only 8 (or 16) devices? > The technical support from the OEM told me that "the onboard > SAS controller maximum amount of supported harddrives is 16pcs" > and "if you are planning on using more than 16 drives then you > have to use a PCI-E card based SAS controller with external ports > (which Supermicro does not sell)" > and both statements sound insane to me! > First, because the specs for 3008 says something else and i dont know > how one can artificially reduce the number of supported hdds > (beside the firmware - but why would one do that?) and > the second statement is just hogwash as the externl/internal status of > the ports have nothing to do with the sas cascading and the number of > devices supported!! (and of course is really cheap to convert an internal > port to an external port with a bracket) > So, i ask you guys that have more knowledge and expertise: was this > Senior Application Engineer that answered me a total incompetent? > > Thank you! > Adrian > > > _______________________________________________ > CentOS mailing list > CentOS at centos.org > https://lists.centos.org/mailman/listinfo/centos > >