Re: Multi-Actuator SAS HDD First Look

On Wed, Apr 18, 2018 at 10:20 AM, Bart Van Assche wrote: > On Wed, 2018-04-18 at 05:16 -0600, Tim Walker wrote: >> It would be good if we could set up an informal meeting time and >> location at LSFMM to discuss these dual actuator topics. so far you, >> Doug, Hannes, and

Re: Multi-Actuator SAS HDD First Look

On Wed, 2018-04-18 at 05:16 -0600, Tim Walker wrote: > It would be good if we could set up an informal meeting time and > location at LSFMM to discuss these dual actuator topics. so far you, > Doug, Hannes, and Christoph have expressed the most interest, plus > Damien. Can we set an hour aside one

Re: Multi-Actuator SAS HDD First Look

On Sun, Apr 15, 2018 at 10:31 PM, Bart Van Assche wrote: > On Sun, 2018-04-15 at 19:35 -0600, Tim Walker wrote: >> I also believe the dual-actuator, or any significant HDD parallelism, >> would map well onto an NVMe target, or NVMe-oF behind nvmet. Maybe a >> lightweight

Re: Multi-Actuator SAS HDD First Look

On Sun, 2018-04-15 at 19:35 -0600, Tim Walker wrote: > I also believe the dual-actuator, or any significant HDD parallelism, > would map well onto an NVMe target, or NVMe-oF behind nvmet. Maybe a > lightweight virtual NVMe controller that would efficiently present the > HDD logs/mode pages/etc via

Re: Multi-Actuator SAS HDD First Look

On Mon, Apr 9, 2018 at 10:02 AM, Douglas Gilbert wrote: > > On 2018-04-09 02:17 AM, Hannes Reinecke wrote: >> >> On 04/09/2018 04:08 AM, Tim Walker wrote: >>> >>> On Fri, Apr 6, 2018 at 11:09 AM, Douglas Gilbert >>> wrote: On

Re: Multi-Actuator SAS HDD First Look

On 2018-04-09 02:17 AM, Hannes Reinecke wrote: On 04/09/2018 04:08 AM, Tim Walker wrote: On Fri, Apr 6, 2018 at 11:09 AM, Douglas Gilbert wrote: On 2018-04-06 02:42 AM, Christoph Hellwig wrote: On Fri, Apr 06, 2018 at 08:24:18AM +0200, Hannes Reinecke wrote: Ah.

Re: Multi-Actuator SAS HDD First Look

On Fri, Apr 06, 2018 at 01:09:08PM -0400, Douglas Gilbert wrote: > So you found a document that outlines NVMe's architecture! Could you > share the url (no marketing BS, please)? You can always take a look at the actual spec:

Re: Multi-Actuator SAS HDD First Look

On 04/09/2018 04:08 AM, Tim Walker wrote: > On Fri, Apr 6, 2018 at 11:09 AM, Douglas Gilbert > wrote: >> >> On 2018-04-06 02:42 AM, Christoph Hellwig wrote: >>> >>> On Fri, Apr 06, 2018 at 08:24:18AM +0200, Hannes Reinecke wrote: Ah. Far better. What about

Re: Multi-Actuator SAS HDD First Look

On Fri, Apr 6, 2018 at 11:09 AM, Douglas Gilbert wrote: > > On 2018-04-06 02:42 AM, Christoph Hellwig wrote: >> >> On Fri, Apr 06, 2018 at 08:24:18AM +0200, Hannes Reinecke wrote: >>> >>> Ah. Far better. >>> What about delegating FORMAT UNIT to the control LUN, and not >>>

Re: Multi-Actuator SAS HDD First Look

On 2018-04-06 02:42 AM, Christoph Hellwig wrote: On Fri, Apr 06, 2018 at 08:24:18AM +0200, Hannes Reinecke wrote: Ah. Far better. What about delegating FORMAT UNIT to the control LUN, and not implementing it for the individual disk LUNs? That would make an even stronger case for having a

Re: Multi-Actuator SAS HDD First Look

On Fri, Apr 06, 2018 at 08:24:18AM +0200, Hannes Reinecke wrote: > Ah. Far better. > What about delegating FORMAT UNIT to the control LUN, and not > implementing it for the individual disk LUNs? > That would make an even stronger case for having a control LUN; > with that there wouldn't be any

Re: Multi-Actuator SAS HDD First Look

On Thu, 5 Apr 2018 17:43:46 -0600 Tim Walker wrote: > On Tue, Apr 3, 2018 at 1:46 AM, Christoph Hellwig > wrote: > > On Sat, Mar 31, 2018 at 01:03:46PM +0200, Hannes Reinecke wrote: > >> Actually I would propose to have a 'management' LUN at LUN0,

Re: Multi-Actuator SAS HDD First Look

On 2018-04-05 07:43 PM, Tim Walker wrote: On Tue, Apr 3, 2018 at 1:46 AM, Christoph Hellwig wrote: On Sat, Mar 31, 2018 at 01:03:46PM +0200, Hannes Reinecke wrote: Actually I would propose to have a 'management' LUN at LUN0, who could handle all the device-wide commands

Re: Multi-Actuator SAS HDD First Look

On Tue, Apr 3, 2018 at 1:46 AM, Christoph Hellwig wrote: > On Sat, Mar 31, 2018 at 01:03:46PM +0200, Hannes Reinecke wrote: >> Actually I would propose to have a 'management' LUN at LUN0, who could >> handle all the device-wide commands (eg things like START STOP UNIT, >>

Re: Multi-Actuator SAS HDD First Look

On Sat, Mar 31, 2018 at 01:03:46PM +0200, Hannes Reinecke wrote: > Actually I would propose to have a 'management' LUN at LUN0, who could > handle all the device-wide commands (eg things like START STOP UNIT, > firmware update, or even SMART commands), and ignoring them for the > remaining LUNs.

Re: Multi-Actuator SAS HDD First Look

On Mon, Apr 2, 2018 at 10:29 AM, Douglas Gilbert wrote: > On 2018-04-02 11:34 AM, Tim Walker wrote: >> >> On Sat, Mar 31, 2018 at 10:52 AM, Douglas Gilbert >> wrote: >>> >>> On 2018-03-30 04:01 PM, Bart Van Assche wrote: On Fri,

Re: Multi-Actuator SAS HDD First Look

On 2018-04-02 11:34 AM, Tim Walker wrote: On Sat, Mar 31, 2018 at 10:52 AM, Douglas Gilbert wrote: On 2018-03-30 04:01 PM, Bart Van Assche wrote: On Fri, 2018-03-30 at 12:36 -0600, Tim Walker wrote: Yes I will be there to discuss the multi-LUN approach. I wanted to

Re: Multi-Actuator SAS HDD First Look

On Sat, Mar 31, 2018 at 10:52 AM, Douglas Gilbert wrote: > On 2018-03-30 04:01 PM, Bart Van Assche wrote: >> >> On Fri, 2018-03-30 at 12:36 -0600, Tim Walker wrote: >>> >>> Yes I will be there to discuss the multi-LUN approach. I wanted to get >>> these interface details

Re: Multi-Actuator SAS HDD First Look

On 2018-03-30 04:01 PM, Bart Van Assche wrote: On Fri, 2018-03-30 at 12:36 -0600, Tim Walker wrote: Yes I will be there to discuss the multi-LUN approach. I wanted to get these interface details out so we could have some background and perhaps folks would come with ideas. I don't have much more

Re: Multi-Actuator SAS HDD First Look

On 03/30/2018 08:07 PM, Tim Walker wrote: > Hello- > > Concerning how we are currently allocating commands to LUNs or the > device as a whole, here is a list based on the current two LUN model. > This model has LUN0 & LUN1, both reporting 1/2 the total storage. Our > definition of "device based"

Re: Multi-Actuator SAS HDD First Look

On 03/30/2018 03:07 PM, Tim Walker wrote: > Hi Doug- > > Currently, the dual actuator firmware safely spins the drive down if > either LUN receives the START STOP UNIT command. In other words, if > LUN1 receives the command, it will flush any dirty data from LUN1l and > LUN0, then spin down,

Re: Multi-Actuator SAS HDD First Look

On Fri, 2018-03-30 at 12:36 -0600, Tim Walker wrote: > Yes I will be there to discuss the multi-LUN approach. I wanted to get > these interface details out so we could have some background and > perhaps folks would come with ideas. I don't have much more to put > out, but I will certainly answer

Re: Multi-Actuator SAS HDD First Look

Yes I will be there to discuss the multi-LUN approach. I wanted to get these interface details out so we could have some background and perhaps folks would come with ideas. I don't have much more to put out, but I will certainly answer questions - either on this list or directly. Best regards,

Re: Multi-Actuator SAS HDD First Look

On Fri, 2018-03-30 at 12:21 -0600, Tim Walker wrote: > Yes, the header LUN field. Sorry! > > We hadn't intended to broadcast - we expect to see a LUN specified. > For a device specific command both LUNs will be affected regardless of > which LUN is specified in the transport field. e.g. if we

Re: Multi-Actuator SAS HDD First Look

Hi Bart- Yes, the header LUN field. Sorry! We hadn't intended to broadcast - we expect to see a LUN specified. For a device specific command both LUNs will be affected regardless of which LUN is specified in the transport field. e.g. if we command LUN1 to stop (START STOP UNIT) then LUN0 will

Re: Multi-Actuator SAS HDD First Look

On Fri, 2018-03-30 at 12:07 -0600, Tim Walker wrote: > Concerning how we are currently allocating commands to LUNs or the > device as a whole, here is a list based on the current two LUN model. > This model has LUN0 & LUN1, both reporting 1/2 the total storage. Our > definition of "device based"

Re: Multi-Actuator SAS HDD First Look

Hello- Concerning how we are currently allocating commands to LUNs or the device as a whole, here is a list based on the current two LUN model. This model has LUN0 & LUN1, both reporting 1/2 the total storage. Our definition of "device based" is that it ignores the LUN field and executes the

Re: Multi-Actuator SAS HDD First Look

Hi Doug- Currently, the dual actuator firmware safely spins the drive down if either LUN receives the START STOP UNIT command. In other words, if LUN1 receives the command, it will flush any dirty data from LUN1l and LUN0, then spin down, taking both LUN1 & LUN0 off line. Alternatively, we've

Re: Multi-Actuator SAS HDD First Look

On 2018-03-26 11:08 AM, Hannes Reinecke wrote: On Fri, 23 Mar 2018 08:57:12 -0600 Tim Walker wrote: Seagate announced their split actuator SAS drive, which will probably require some kernel changes for full support. It's targeted at cloud provider JBODs and RAID.

Re: Multi-Actuator SAS HDD First Look

On Fri, 23 Mar 2018 08:57:12 -0600 Tim Walker wrote: > Seagate announced their split actuator SAS drive, which will probably > require some kernel changes for full support. It's targeted at cloud > provider JBODs and RAID. > > Here are some of the drive's architectural

Multi-Actuator SAS HDD First Look

Seagate announced their split actuator SAS drive, which will probably require some kernel changes for full support. It's targeted at cloud provider JBODs and RAID. Here are some of the drive's architectural points. Since the two LUNs share many common components (e.g. spindle) Seagate allocated