Re: Recognizing SMR HDDs

On Thu, May 26, 2016 at 15:29:21 +0200, Gary Jennejohn wrote:
> On Thu, 26 May 2016 08:34:45 -0400
> "Kenneth D. Merry" <ken_at_FreeBSD.ORG> wrote:
> 
> > On Thu, May 26, 2016 at 08:42:53 +0200, Gary Jennejohn wrote:
> > What kind of drive is it?
> > 
> 
> ST8000AS 0002-1NA17Z 0X03

Can you send the output of 'camcontrol inquiry daX -v' and
'camcontrol identify daX -v'?

There is a quirk for that particular drive to identify it as Drive Managed.
When attached behind a SAS controller it looks like this:

# camcontrol inquiry da12 -v
pass12: <ATA ST8000AS0002-1NA AR17> Fixed Direct Access SPC-4 SCSI device
pass12: Serial Number             Z8407Y52
pass12: 600.000MB/s transfers, Command Queueing Enabled

> > Here are some things you can do on any disk to see what it is:
> > 
> > diskinfo -v /dev/daX
> > 
> 
> I don't have the new versions of these utilities installed, so I can't
> get any of this neat diskinfo/zonectl information.
> 
> > # sysctl kern.cam.da.19
> > kern.cam.da.19.sort_io_queue: -1
> > kern.cam.da.19.rotating: 1
> > kern.cam.da.19.unmapped_io: 1
> > kern.cam.da.19.error_inject: 0
> > [ begin SMR fields ]
> > kern.cam.da.19.max_seq_zones: 0
> > kern.cam.da.19.optimal_nonseq_zones: 0
> > kern.cam.da.19.optimal_seq_zones: 0
> > kern.cam.da.19.zone_support: None
> > kern.cam.da.19.zone_mode: Drive Managed
> > [ begin SMR fields ]
> > kern.cam.da.19.minimum_cmd_size: 6
> > kern.cam.da.19.delete_max: 262144
> > kern.cam.da.19.delete_method: NONE
> > 
> 
> My drive shows this;
> sysctl kern.cam.da.0
> kern.cam.da.0.sort_io_queue: -1
> kern.cam.da.0.rotating: 1
> kern.cam.da.0.unmapped_io: 0
> kern.cam.da.0.error_inject: 0
> kern.cam.da.0.max_seq_zones: 0
> kern.cam.da.0.optimal_nonseq_zones: 0
> kern.cam.da.0.optimal_seq_zones: 0
> kern.cam.da.0.zone_support: None
> kern.cam.da.0.zone_mode: Not Zoned <== I guess it can't be managed
> kern.cam.da.0.minimum_cmd_size: 10
> kern.cam.da.0.delete_max: 131072
> kern.cam.da.0.delete_method: NONE
> 
> In fact, the ouput for every one of the 4 drives in the enclosure is
> the same, even though the other three are non-SMR SATA drives.

Yes.  There is something slightly odd about the Inquiry data you pasted
above.  Seagate didn't set the bits in the ATA identify data to mark it as
a Drive Managed drive, so I put in a quirk entry to mark it as Drive
Managed.

Unfortunately with Drive Managed drives that is really all you know.  You
don't know the zone boundaries or states.  But, it is useful to know that
you really should write sequentially for good performance.  (True of any
drive, but especially true with SMR drives.)

Ken
-- 
Kenneth Merry
ken_at_FreeBSD.ORG