Dell PERC5/i SAS5/5IR - RAID monitoring

[Scott Long]

Michael Worobcuk wrote:

>> Tom Judge wrote:
>>
>> As for performance issues with the SAS5/i, there is a problem in  the 
>> controller.  A work arround was created by Scott Long which  created a 
>> sysctl that could be set to cause the controller to turn  on the on 
>> drive write cache's. These changes where commited to  RELENG_6 on 
>> 2007-06-05 21:32:57 UTC.
>>
>>
>> ...
>>
>>>
>>> Here is the original commit log:
>>>
>>> scottl      2007-06-03 23:13:05 UTC
>>>
>>>   FreeBSD src repository
>>>
>>>   Modified files:
>>>     sys/dev/mpt          mpt.c mpt.h mpt_cam.c
>>>   Log:
>>>   mpt.c:
>>>   mpt.h:
>>>           Add support for reading extended configuration pages.
>>>   mpt_cam.c:
>>>           Do a top level topology scan on the SAS controller.  If  
>>> any SATA device are discovered in this scan, send a passthrough  FIS 
>>> to set the write cache.  This is controllable through the  following 
>>> tunable at boot:
>>>
>>>           hw.mpt.enable_sata_wc:
>>>                   -1 = Do not configure, use the controller default
>>>                    0 = Disable the write cache
>>>                    1 = Enable the write cache
>>>
>>>           The default is -1.  This tunable is just a hack and may be
>>>           deprecated in the future.
>>
>>
> 
> I set mpt.enable_sata_wc to 1, as hw.mpt.enable_sata_wc is, AFAIK not  
> tunable in mpt_cam.c. This did not take any effect to the  performance. 
> Is there anything else to change ?
> 

Send me output from bootverbose.  Also ensure that you have the 
following line in your /boot/loader.conf file:

hw.mpt.enable_sata_wc=1

Scott