MFI and passthrough

[Scott Long]

Borja Marcos wrote:
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> On Nov 6, 2007, at 4:02 PM, Scott Long wrote:
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>> Doug Ambrisko wrote:
>>> BTW, it works great in this mode if you know what you are doing :-)
>>
>> Can you explain what that means?  I recommend against it because it's
>> not a well-tested configuration either in FreeBSD or in Dell.  It's not
>> clear, at least to me, how basic things like i/o errors get handled; 
>> does SCSI sense data get consumed by the controller firmware, or is it
>> passed through to the OS without problem?
> 
> Aha, I see. I assumed that the controller would pass the sense data, 
> etc, without problems.
> 
>>> | I do believe that Dell does sell a direct attached disk option for
>>> | the 2950/1950 called the PERC5/e.  It's essentially an LSI MPT-SAS
>>> | controller that directly replaces the PERC5/i card that you have now.
>>> | It should be able to control all 6 disk slots, and can do both SAS
>>> | and SATA.
>>> I've been told the PERC5/e and PERC5/i are the same except for PCI
>>> sub-device ID and are both the mfi(4) RAID controllers.  They do
>>> have a mpt(4) based card but it only supports 4 bays.  I'm not sure
>>> what it's real name is but we have some lying around for random
>>> testing.  I don't leave them in machines.
>>
>> We should get a definitive answer on this.
> 
> We asked our Dell salesman and he confirmed that there's a non disk 
> array card for this machine,
> but it only supports 4 disks, not 6.
> 

Ok, I thought that the 4 disk option just routed the motherboard SATA 
connectors to the backplane, and that there was a 6 disk SAS+SATA option 
that put an MPT card into the slot behind the backplane.  Oh well.

Scott