SAS Raid - mfi driver

[Fredrik Widlund]

Yes, it forces writeback even when the controller has no BBU. Choosing 
WBack itself will default back to WThru. It's dangerous, but I guess it 
should be much less dangerous than using for example softupdates. We 
have little choice until our order of BBUs get here, since the 
performance degradation of wthru would make it unusable for us.

Ivan Voras skrev:
> Fredrik Widlund wrote:
>   
>> Solved my issue with LSI 8480E without BBU. With "write: BadBBU",
>> "cache: enabled", and "io: cached", performance rose to around 200MB/s
>> from 20MB/s.
>>     
>
> I don't know what "BadBBU" is, but from some Googling it seems to be a
> setting that overrides BBU detection, and enables write caching even if
> the system believes BBU is broken or missing. If true, this may be
> dangerous for data consistency.
>
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