Re: [LSF/MM/BPF TOPIC] Multi-actuator HDDs

Tim Walker
2020-02-11T19:23:19Z

On Mon, Feb 10, 2020 at 4:52 PM Dave Chinner <david@fromorbit.com> wrote:
>
> On Mon, Feb 10, 2020 at 12:01:13PM -0600, Muhammad Ahmad wrote:
> > Background:
> > As the capacity of HDDs increases so is the need to increase
> > performance to efficiently utilize this increase in capacity. The
> > current school of thought is to use Multi-Actuators to increase
> > spinning disk performance. Seagate has already announced it’s SAS
> > Dual-Lun, Dual-Actuator device. [1]
> >
> > Discussion Proposal:
> > What impacts multi-actuator HDDs has on the linux storage stack?
> >
> > A discussion on the pros & cons of accessing the actuators through a
> > single combined LUN or multiple individual LUNs? In the single LUN
> > scenario, how should the device communicate it’s LBA to actuator
> > mapping? In the case of multi-lun, how should we manage commands that
> > affect both actuators?
>
> What ground does this cover that wasn't discussed a couple of years
> ago at LSFMM?
>
> https://urldefense.proofpoint.com/v2/url?u=https-3A__lwn.net_Articles_753652_&d=DwIDaQ&c=IGDlg0lD0b-nebmJJ0Kp8A&r=NW1X0yRHNNEluZ8sOGXBxCbQJZPWcIkPT0Uy3ynVsFU&m=2Eb6xxsYMqNOn4F3Yiola3ef2BTCKKg06zpnqJ_m1c8&s=JtxAw3Y13PHlYJygS847dBUVRXeM061Snm3hq01DFlY&e=
>
> Cheers,
>
> Dave.
> --
> Dave Chinner
> david@fromorbit.com

Hi all-

The multi-actuator fundamentals remain the same from a couple of years
ago. One development is to combine the actuators' address spaces into
a single LUN. We'd like to show you a couple of system block diagrams,
and talk about the queue management and command scheduling.

Best regards,
-Tim

--
Tim Walker
Product Design Systems Engineering, Seagate Technology
(303) 775-3770