OT-ish SATA port replicators vs. SAS "expanders"

[Mike Tancsa]

On 11/16/2014 7:26 PM, Brandon Vincent wrote:
> On Sun, Nov 16, 2014 at 4:51 PM, Mike Tancsa <mike at sentex.net> wrote:
>> I don think a port multiplier is the same as a SAS expander and a SAS/SATA
>> controller does not necessarily support port multipliers.
>
> You're absolutely correct. The SATA specifications if I recall
> correctly, outline that providing support for port multipliers is
> optional. Not to mention, the vast majority of chipsets that do have
> support for port multipliers only provide the slower command-based
> switching method [1], The LSI SAS 2008 chipset is not what you
> typically find on the cheap consumer "fake RAID" cards which most
> people have [2].
>
> Most people who purchase this card are purchasing it for SAS, true
> RAID, performance, and reliability. Thus, LSI is only going to provide
> support for the far superior SAS expander technology.


We also got rid of all those external 4 port PMs and replaced it with one
NORCO RPC-4220
The pricing is quite reasonable and less expensive then using PMs and so 
far MUCH more reliable.

	---Mike



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