N-way mirror read speedup in zfsonlinux

[Steven Hartland]

----- Original Message ----- 
From: "Alexander Motin" <mav at FreeBSD.org>


> On 16.08.2013 00:41, Steven Hartland wrote:
>> ----- Original Message ----- From: "Alexander Motin" <mav at FreeBSD.org>
>>
>>> On 15.08.2013 23:00, Steven Hartland wrote:
>>>> ----- Original Message ----- From: "Alexander Motin" <mav at FreeBSD.org>
>>>>> 4) I don't very like idea of expanding struct disk every time
>>>>> (especially not at the end). While that is probably easier then
>>>>> alternatives, now we have d_getattr method specifically to avoid that.
>>>>
>>>> I see what you mean but it needs to be stored somewhere otherwise
>>>> we're going to have to query the device every time or did you have
>>>> something else specific in mind?
>>>
>>> I was thinking about storing it in da/ada periph softc's and modifying
>>> dagetattr()/adagetattr().
>>
>> That would make it more work to add non-cam based support such as mfi.
> 
> That is why I have told that indeed proposed implementation is easier 
> then alternatives. :) BTW, does RAID controllers like mfi can provide 
> such details?

When used in JBOD mode yes we should be able to access all the normal
device data.

    Regards
    Steve

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