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

Muhammad Ahmad
2020-03-03T16:59:31Z

Are the topics for LSF/MM/BPF finalized? Trying to see if this topic made the cut or not.

Regards,
-Muhammad

From: Timothy T. Walker <tim.t.walker@seagate.com>

Sent: Tuesday, February 11, 2020 1:23 PM

To: Dave Chinner <david@fromorbit.com>

Cc: Muhammad Ahmad <muhammad.ahmad@seagate.com>; linux-fsdevel@vger.kernel.org <linux-fsdevel@vger.kernel.org>; linux-block@vger.kernel.org <linux-block@vger.kernel.org>; linux-scsi <linux-scsi@vger.kernel.org>

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

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