Dell PERC5/i SAS5/5IR - RAID monitoring

[Michael Worobcuk]

> 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 ?

--
Michael