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@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
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