Dual-port SAS HDD ?

[Alan Somers]

On Thu, May 6, 2021 at 4:52 AM Ben RUBSON <ben.rubson at gmx.com> wrote:

> Hi,
>
> I'm building a new ZFS pool from scratch, choosing my own hardware etc...
> For sure I'll go for the standard SAS2008 / SAS3008 controller.
>
> However, I'm wondering whether or not I should absolutely go for dual-port
> SAS HDD (with dual backplane, controller...).
> I have some difficulties to find enterprise grade dual port SAS HDD.
> HGST used to provide Ultrastar SAS HDD which were dual-port.
> However, strangely, Western Digital does not advertise their Ultrastar DC
> SAS HDD as bringing dual-port, so I guess they're not.
>
> Any thoughts / advices regarding this topic ?
>
> Many thanks for your help,
>
> Kind regards,
>
> Ben
>

It's just a matter of high availability.  Can you tolerate an outage if a
JBOD I/O controller fails?  If so, then you don't need dual-port.  But
server crashes are more common than JBOD I/O controller failures.  So you
should worry more about that.