Dell PERC5/i SAS5/5IR - RAID monitoring

[Michael Worobcuk]

Am 21.07.2007 um 01:15 schrieb Tom Judge:

> Michael Worobcuk wrote:
>> Am 21.07.2007 um 00:18 schrieb Tom Judge:
>>> 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 ?
>>>
>>> Not that I know of, do you have SAS or SATA disks attached to the  
>>> controller?
>> yes, SAS.
>
> In that case the above sysctl is not going to work for you as as  
> the name suggests it is only for sata devices.
>
> For someone with a bit more SCSI experience than me: Could this be  
> solved by setting the WCE (Write cache enable) bit in the modepage  
> (8) on sas devices if it is not already set?  The driver could make  
> this change on SAS devices during the topology scan in similar way  
> to the way it does for SATA devices?
>
> Tom

hey sorry. Already a bit tired yesterday. I have SATA drives  
connected, in my mind was the name: sas5ir. But I have SATA DRIVES.
sorry again.


Michael