svn commit: r308217 - in head/sys/dev: mpr mps

[Scott Long]

> On Nov 4, 2016, at 3:18 AM, Harry Schmalzbauer <freebsd at omnilan.de> wrote:
> 
> Bezüglich Scott Long's Nachricht vom 02.11.2016 16:13 (localtime):
>> Author: scottl
>> Date: Wed Nov  2 15:13:25 2016
>> New Revision: 308217
>> URL: https://svnweb.freebsd.org/changeset/base/308217
>> 
>> Log:
>>  Add a fallback to the device mapper logic.  We've seen systems in the field
>>  that are apparently misconfigured by the manufacturer and cause the mapping
>>  logic to fail.  The fallback allows drive numbers to be assigned based on the
>>  PHY number that they're attached to.  Add sysctls and tunables to overrid
>>  this new behavior, but they should be considered only necessary for debugging.
> 
> Thanks a lot, this is welcome not only for debugging!
> 
> I had a hard time finding out how to get rid of static
> driveserial-targetID assigning.
> And more surprising, this affects only IT-fw. When using the same
> controller in IR-mode, mapping is done (correctly) slot-based.
> In IT-mode, every drive got a consecutive target ID which was static,
> and even persistent over firmware updates. There's only one possibility
> with LSIUtil(1.71) to erase /"persitent non-manufacturing config pages/".
> But I guess this hard drive-targetID assigning is triggered by the
> driver, namely the mps(4) in FreeBSD.
> I did quick tests on windows and IT-mode, where I think I saw slot (or
> Phy?) based assigning.
> 
> If it's really mps(4) who decides to store driveserial-targetID
> numbering in the /"persitent non-manufacturing config pages/" of the
> controller, mpsutil(8) should be able to reset. Otherwise replacing
> failed drives, or - even mor confusing - rearranging drive/zpool layouts
> is very unsatisfying.
> 
> Maybe "-1" should be mentioned with sysctl decription, otherwise this is
> another very hard to find/influence behaviour.
> 
> 

Thanks for the feedback.  For the record, this problem happens on a
Supermicro X10SDV-7TP4F motherboard.  It appears that the support
logic around the LSI controller is mis-configured to show the SAS ports
being part of an enclosure with 0 slots, instead of 8.  This confuses
the device mapper logic in the driver that activates if the controller NVRAM
doesn’t specify a pre-existing mapping.  Typically this is not the default,
the NVRAM persistent mappings are the default and are used by the driver,
so I considered this problem to be unique to our deployment.  Maybe it’s
more of a problem than I estimated?  Anyways, sounds like this new
functionality should be properly documented in the driver.

Scott