Re: SAS expander

On 11/10/2024 2:07 PM, Grant Taylor wrote:

On 11/10/24 13:48, Don Y wrote:

I have several DAS boxes that a have built-in SAS expanders (to put up to
90 drives on a SAS cable).  But, ALL must be SAS or ALL must be SATA.
I am not sure if that is a requirement of the hardware or firmware
(but it is a reasonable one)

 That sounds like a potential gotcha.  I don't know if it's spec and / or implementation.

I know the *chips* that exist for this support both.  But, I am not
sure how much hand-holding is needed to get them to support both.
Or, if a "mix" is even possible in the hardware.

Do these just mechanically package the drives?  Or, do they include a
SAS expander and present to the host as a SAS interface?  (that would
be cool!)

 I've seen both.
 I think it depends on the number of drives that go in the enclosure and the physical size thereof.  It seems as if the ones that hold fewer drives might simply be pass through while the ones that hold more drives probably have expanders in them.

I thought SAS/SATA drives were point-to-point wired?  I.e., *can*
you hang two drives on a single cable without any extra electronics?
My initial thought was just to get an expander "card" -- or cards -- that
had "many" SAS/SATA ports on it and cable it to the drives wherever I
could make them fit (SSDs being so lightweight that I figured I could use
double-sided tape to secure them to each other, the sides of the case, etc.)