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@xxxxxxx>
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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