LSI - MR-Fusion controller driver <mrsas> patch and man page

[Doug Ambrisko]

On Mon, Mar 24, 2014 at 09:03:43AM +0100, Borja Marcos wrote:
| 
| On Mar 21, 2014, at 5:09 PM, Doug Ambrisko wrote:
| 
| > Do you have a simple test case for that?  There were issues in the SCSI
| > command translation which should have been fixed via switching it to use
| > the CAM translation code.  Can you try it via a RAID volume of one disk?
| 
| Yes, I tried all those possibilities. "syspd" devices, passthrough 
| (same result, corrruption) and when creating single-disk RAID0 volumes 
| it worked, no corruption.

Okay, so you don't have and simple test case to show this.  What are
you currently doing?  I would think the syspd and the single disk RAID0
should be very similar.  I'll take a look at that.
 
| Just in case I tried with SSDs (Samsung EVO  840 and OCZ Vertex 4) and 
| Seagate SAS disks.

So it seems generic.  Size of disk might be useful.
 
| > | The server is not in production, so I have no problems to try drivers, etc.
| > 
| > You could try the LSI mrsas and see if the corruption goes away and then
| > we could try to isolate the difference.  mrsas does not support CAM
| > passthrough.  If both drivers are loaded in the kernel, you can prevent
| > mfi from attaching and let mrsas attach via the tunable:
| > 	hw.mfi.mrsas_enable=1
| > The mrsas device come up /dev/da* there are no aliases yet to the mfi one's.
| > Also mfiutil won't work with mrsas but MegaCli/StorCli should.  If you want
| > to use mfiutil, you can switch to mfi to set that up and then switch back
| > to mrsas.  I need to finish the mrsas compat work so mfiutil can work
| > on it.  It's a little more complicated then I hoped.
| 
| Actually I think that converting passthrough disks to "mfisyspd" or an
| equivalent is a bad idea, unless, of course, there's a compelling reason
| I don't realize. For instance, if you are using SSDs you need access to
| the TRIM command.
| 
| So, if I can vote, I vote with arms and legs for "da" devices in case it's
| a passthough.

Nothing is planned to be removed from mfi.  However, LSI would like mrsas
to be used on newer cards.  We've let people LSI know that people use
the pass through mode and having the logical volumes come up as /dev/daX
and pass through would be confusing.  Granted mrsas doesn't support pass
through so that isn't a problem.
 
| It's not a pressing need, I installed a LSI2008 card and I connected the 
| SAS backplane to it, so for now the Invader
| is a non-problem, but if it will help to run some tests with the mps 
| driver I can certainly do it.

The mps driver is a different thing, mrsas is LSI's replacement for mfi
with newer cards.  So if you could try syspd and single RAID 0 test
with mrsas that would be great to see if that shows the same pattern
of syspd failing with mfi and passing with single RAID 0.  Again,
the logical volumes will show up as /dev/da* with no pass through
devices.  If I can reproduce the problem then I can look into here
or others might be able to find the solution.

Thanks,

Doug A.